Specify home path in java-maven devfile

Since OpenShift starts containers with a random UID (which has no
username associated with it), maven running on OpenShift cannot figure
out where to place the .m2 repository. This commit explicitly sets the
-Duser.home parameter to /home/user to match the mounted .m2 volume.

Signed-off-by: Angel Misevski <amisevsk@redhat.com>

devfiles/java-maven/devfile.yaml

@@ -17,7 +17,8 @@ components:
       - name: MAVEN_OPTS
         value: "-XX:MaxRAMPercentage=50 -XX:+UseParallelGC -XX:MinHeapFreeRatio=10
           -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90
-          -Dsun.zip.disableMemoryMapping=true -Xms20m -Djava.security.egd=file:/dev/./urandom"
+          -Dsun.zip.disableMemoryMapping=true -Xms20m -Djava.security.egd=file:/dev/./urandom
+          -Duser.home=/home/user"
       - name: JAVA_OPTS
         value: "-XX:MaxRAMPercentage=50 -XX:+UseParallelGC -XX:MinHeapFreeRatio=10
           -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90