There is still /opt/rh/... path present in uncomemnted line after postinstall in conf.d/mod_cluster.conf file.

MemManagerFile /opt/rh/jbcs-httpd24/root/var/cache/mod_cluster

Root cause: change between this and prev. version in config file
From: MemManagerFile cache/mod_cluster
To: MemManagerFile /opt/rh/jbcs-httpd24/root/var/cache/mod_cluster
POSTINSTALL script looks for pattern: MemManagerFile cache/mod_cluster

sed -i -e "s:MemManagerFile cache/mod_cluster:MemManagerFile $currentDir/cache/mod_cluster:" conf.d/mod_cluster.conf

Expect something like:

sed -i -e "s:MemManagerFile.*cache/mod_cluster:MemManagerFile $currentDir/cache/mod_cluster:" conf.d/mod_cluster.conf