Remove JAVA_HOME export from pants script.
Remove JAVA_HOME export from pants script.

This is only needed internally and is now set in env.sh.

(sapling split of 46dbf35ee4d3c7731a6efde340538b63bb7caac8)
foursquare/fsqio,foursquare/fsqio,foursquare/fsqio,foursquare/fsqio,foursquare/fsqio