If the security provider throws a NoAccessException, treat that as though it
returned false (but use the thrown object to provide better stack information).

@rev amcculloch@
@bug W-1902571@
Auto-activate ubuntu12 profile if environment variable UBUNTU12 is set.

I would have preferred to use <os><version>...</version></os>, but it seems
that <os> doesn't allow ranges or even prefixing.  Activation by <jdk> would,
but not <os>.  And, really, some Linux kernel 3.2-or-higher might not be
*Ubuntu* 12, anyway, so maybe this is righteous anyway.

@rev eanderson@
Merging origin/fabbott/master-pending-ub12 into master