This CR is for addressing JIRA RT-16581.
the machine has both 6u26 and 7 java plugin registered:
FF will go through the MozillaPlugins reg. keys in alphbetical order and will attempt to load the dll in that order.
Without the 1.6.0_26 key, FF will use the jre7 version of java plugin.
This bug will need to be fixed in the fx installer.
During install, fx installer should update the @java.com/JavaPlugin reg. key instead of adding a new one.
During uninstall, fx installer should update the @java.com/JavaPlugin reg. key to point to the remaining latest version of java plugin on the machine.