Bump java_xmx from 2G to 4G

The java_xmx value in Puppet for the -Xmx JAVA_OPTS variable was
increased 10 days ago following a timeout on the dev server with an
upload.  Ran into it again during a large branching of Horizon
translations, so now increasing it to 4G following analysis of
server usage to confirm it can take the load.

Change-Id: Iee63c91456ad8f17b0a32732f6610416b6c5b987

manifests/wildfly.pp

@@ -28,7 +28,7 @@ class zanata::wildfly(
     install_source => $wildfly_install_source,
     config         => 'standalone.xml',
     java_home      => '/usr/lib/jvm/java-7-openjdk-amd64/jre/',
-    java_xmx       => '2048m',
+    java_xmx       => '4096m',
     require        => Package['openjdk-7-jre-headless'],
   }
 }