Changing nightly script to set $platform to linux64 if running on a 64-bit linux machine so that we can more easily distinguish between John's nightly linux runs and ours.
Changing nightly script to set $platform to
linux64 if running on a 64-bit linux machine
so that we can more easily distinguish
between John's nightly linux runs and ours.

Also, disabled the caching of UW source
trees unless it's my linux cron job.


git-svn-id: 88467cb1fb04b8a755be7e1ee1026be4190196ef@2340 3a8e244f-b0f2-452b-bcba-4c88e055c3ca

sungeunchoi/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,sungeunchoi/chapel,hildeth/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,chizarlicious/chapel,CoryMcCartan/chapel,hildeth/chapel,sungeunchoi/chapel,chizarlicious/chapel,sungeunchoi/chapel,sungeunchoi/chapel,sungeunchoi/chapel,chizarlicious/chapel,chizarlicious/chapel,sungeunchoi/chapel,sungeunchoi/chapel