Don't generate compiled bytecode files for skeleton generator in the application directory (PY-15907)

This fix disabled the generation of compiled bytecode files only
for Python >= 2.6 in non read-only directories. Having new files inside
the app directory breaks a Mac OS X security policy regarding
application signing and it might result in the "incoming network
connections" warning (not verified yet).

python/helpers/generator3.py

@@ -1,6 +1,12 @@
 # encoding: utf-8
 import atexit
 import zipfile
+import sys
+
+
+if hasattr(sys, 'dont_write_bytecode'):
+    sys.dont_write_bytecode = True
+
 
 # TODO: Move all CLR-specific functions to clr_tools