Only use vault.centos.org (java-native-access#237)

Motivation:

The third-party repos did turn out to be quite unstable.

Modifications:

- Just use vault.centos.org
- Use devtoolset-7

Result:

Hopefully more stable builds

docker/Dockerfile.centos6

@@ -7,12 +7,9 @@ ENV CMAKE_VERSION $CMAKE_VERSION_BASE.2
 ENV NINJA_VERSION 1.7.2
 ENV GO_VERSION 1.9.3
 
-# Update as we need to use the vault now.
+# Update yum repos as we need to use the vault now.
 RUN sed -i -e 's/^mirrorlist/#mirrorlist/g' -e 's/^#baseurl=http:\/\/mirror.centos.org\/centos\/$releasever\//baseurl=https:\/\/vault.centos.org\/6.10\//g' /etc/yum.repos.d/CentOS-Base.repo
 
-# We want to have git 2.x for the maven scm plugin
-RUN yum install -y http://opensource.wandisco.com/centos/6/git/x86_64/wandisco-git-release-6-1.noarch.rpm
-
 # install dependencies
 RUN yum install -y \
  apr-devel \
@@ -33,26 +30,18 @@ RUN yum install -y \
 RUN mkdir $SOURCE_DIR
 WORKDIR $SOURCE_DIR
 
-RUN wget -q https://cmake.org/files/v$CMAKE_VERSION_BASE/cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && tar zxf cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && mv cmake-$CMAKE_VERSION-Linux-x86_64 /opt/ && echo 'PATH=/opt/cmake-$CMAKE_VERSION-Linux-x86_64/bin:$PATH' >> ~/.bashrc
+RUN yum install -y centos-release-scl
+# Update repository urls as we need to use the vault now.
+RUN sed -i -e 's/^mirrorlist/#mirrorlist/g' -e 's/^# baseurl=http:\/\/mirror.centos.org\/centos\/6\//baseurl=https:\/\/vault.centos.org\/centos\/6\//g' /etc/yum.repos.d/CentOS-SCLo-scl.repo
+RUN sed -i -e 's/^mirrorlist/#mirrorlist/g' -e 's/^#baseurl=http:\/\/mirror.centos.org\/centos\/6\//baseurl=https:\/\/vault.centos.org\/centos\/6\//g' /etc/yum.repos.d/CentOS-SCLo-scl-rh.repo
 
-RUN wget -q https://github.com/ninja-build/ninja/releases/download/v$NINJA_VERSION/ninja-linux.zip && unzip ninja-linux.zip && mkdir -p /opt/ninja-$NINJA_VERSION/bin && mv ninja /opt/ninja-$NINJA_VERSION/bin && echo 'PATH=/opt/ninja-$NINJA_VERSION/bin:$PATH' >> ~/.bashrc
+RUN yum -y install devtoolset-7-gcc devtoolset-7-gcc-c++
+RUN echo 'source /opt/rh/devtoolset-7/enable' >> ~/.bashrc
 
+RUN wget -q https://cmake.org/files/v$CMAKE_VERSION_BASE/cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && tar zxf cmake-$CMAKE_VERSION-Linux-x86_64.tar.gz && mv cmake-$CMAKE_VERSION-Linux-x86_64 /opt/ && echo 'PATH=/opt/cmake-$CMAKE_VERSION-Linux-x86_64/bin:$PATH' >> ~/.bashrc
+RUN wget -q https://github.com/ninja-build/ninja/releases/download/v$NINJA_VERSION/ninja-linux.zip && unzip ninja-linux.zip && mkdir -p /opt/ninja-$NINJA_VERSION/bin && mv ninja /opt/ninja-$NINJA_VERSION/bin && echo 'PATH=/opt/ninja-$NINJA_VERSION/bin:$PATH' >> ~/.bashrc
 RUN wget -q https://storage.googleapis.com/golang/go$GO_VERSION.linux-amd64.tar.gz && tar zxf go$GO_VERSION.linux-amd64.tar.gz && mv go /opt/ && echo 'PATH=/opt/go/bin:$PATH' >> ~/.bashrc && echo 'export GOROOT=/opt/go/' >> ~/.bashrc
 
-RUN wget -q https://linuxsoft.cern.ch/cern/scl/RPM-GPG-KEY-cern && mv RPM-GPG-KEY-cern /etc/pki/rpm-gpg/
-RUN wget -q https://linuxsoft.cern.ch/cern/scl/slc6-scl.repo && mv slc6-scl.repo /etc/yum.repos.d
-RUN yum install -y devtoolset-3-gcc-c++
-RUN echo 'source /opt/rh/devtoolset-3/enable' >> ~/.bashrc
-
-# This is workaround to be able to compile boringssl with -DOPENSSL_C11_ATOMIC as while we use a recent gcc installation it still needs some
-# help to define static_assert(...) as otherwise the compilation will fail due the system installed assert.h which missed this definition. 
-run mkdir ~/.include
-run echo '#include "/usr/include/assert.h"' >>  ~/.include/assert.h
-run echo '#define static_assert _Static_assert'  >>  ~/.include/assert.h
-run echo 'export C_INCLUDE_PATH="$HOME/.include/"' >>  ~/.bashrc
-# Needed to compile against old glibc
-run echo 'export LDFLAGS=-lrt' >>  ~/.bashrc
-
 ARG java_version=adopt@1.8.0-275
 ENV JAVA_VERSION $java_version
 # installing java with jabba
@@ -73,6 +62,15 @@ RUN echo 'PATH=/opt/apache-maven-3.6.3/bin/:$PATH' >> ~/.bashrc
 ENV PATH /opt/apache-maven-3.6.3/bin/:$PATH
 ENV JAVA_HOME /jdk/
 
+# This is workaround to be able to compile boringssl with -DOPENSSL_C11_ATOMIC as while we use a recent gcc installation it still needs some
+# help to define static_assert(...) as otherwise the compilation will fail due the system installed assert.h which missed this definition.
+RUN mkdir ~/.include
+RUN echo '#include "/usr/include/assert.h"' >>  ~/.include/assert.h
+RUN echo '#define static_assert _Static_assert'  >>  ~/.include/assert.h
+RUN echo 'export C_INCLUDE_PATH="$HOME/.include/"' >>  ~/.bashrc
+# Needed to compile against old glibc
+RUN echo 'export LDFLAGS=-lrt' >>  ~/.bashrc
+
 COPY ./pom.xml $SOURCE_DIR/pom.xml
 WORKDIR $SOURCE_DIR
 RUN /bin/bash -c 'source $HOME/.bashrc && mvn dependency:go-offline surefire:test -ntp && rm -rf target'