Factor in the jvm version string into the nailgun executor fingerprint
Review Request #1122 - Created Oct. 6, 2014 and submitted
In some configurations, the path to the 'java' executable stays the same but can be manipulated to a different version via a symlink or environment variable.
This causes a mismatch between the already running nailgun server and the jvm that Pants thinks it has chosen.
Manual testing to make sure that ng servier is killed if symlink to java executable is changed.
Writing a unit test for this looked prohibitivly difficult.