CI failed to use javac 1.8

This job just failed after merged cause it didn't find javac http://jenkins.ovirt.org/job/ovirt-engine_3.6_check-merged-fc23-x86_64/88... An excerpt from the error: ``` *08:55:42* [INFO] ------------------------------------------------------------------------*08:55:42* [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project jboss-modules-maven-plugin: Compilation failure*08:55:42* [ERROR] Unable to locate the Javac Compiler in:*08:55:42* [ERROR] /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.92-4.b14.fc23.x86_64/jre/../lib/tools.jar*08:55:42* [ERROR] Please ensure you are using JDK 1.4 or above and*08:55:42* [ERROR] not a JRE (the com.sun.tools.javac.Main class is required).*08:55:42* [ERROR] In most cases you can change the location of your Java*08:55:42* [ERROR] installation by setting the JAVA_HOME environment variable.*08:55:42* [ERROR] -> [Help 1] ```