Fix zfs-kmod builds when using rpm >= 4.14

With rpm-software-management/rpm@5e94633 a package version containing
invalid characters (most commonly a double '-') causes the kmod package
generation to terminate with an error.  This change takes advantage of
the newly introduced rpm macro "_wrong_version_format_terminate_build"
to allow kmod packages to be built.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:  loli10K <ezomori.nozomu@gmail.com>
Closes #7284

config/zfs-build.m4

@@ -210,6 +210,7 @@ AC_DEFUN([ZFS_AC_RPM], [
 	RPM_DEFINE_KMOD+=' --define "require_splobj $(SPL_OBJ)"'
 	RPM_DEFINE_KMOD+=' --define "ksrc $(LINUX)"'
 	RPM_DEFINE_KMOD+=' --define "kobj $(LINUX_OBJ)"'
+	RPM_DEFINE_KMOD+=' --define "_wrong_version_format_terminate_build 0"'
 
 	RPM_DEFINE_DKMS=''