Force set-xcode-analyzer to use the system version of Python installed on OS X.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147483 91177308-0d34-0410-b5e6-96231b3b80d8

tools/scan-build/set-xcode-analyzer

-#!/usr/bin/env python
+#!/usr/bin/python
+
+# [PR 11661] Note that we hardwire to /usr/bin/python because we
+# want to the use the system version of Python on Mac OS X.
+# This one has the scripting bridge enabled.
 
 import os
 import sys