<rdar://problem/13370286>

Fixed a case there the OperatingSystemPython would try to access and play with SBValue objects when the process' public run lock was taken. Prior to this fix, all attempts to run any SBValue functions would fail if run from the private state thread (like updating the thread list). Now we have two run locks, one for public (all threads except the private state thread) and one for private.

llvm-svn: 179329