Update PGP keys during _PostRepoUpgrade in sync

Previously, if a key was added, a client wouldn't add the key during
the sync step.  This would cause issues if a new key were added and a
subsequent release were signed by that key.

Change-Id: I4fac317573cd9d0e8da62aa42e00faf08bfeb26c

main.py

@@ -23,6 +23,7 @@ if __name__ == '__main__':
 del magic
 
 import getpass
+import imp
 import netrc
 import optparse
 import os
@@ -167,16 +168,15 @@ def _MyRepoPath():
 def _MyWrapperPath():
   return os.path.join(os.path.dirname(__file__), 'repo')
 
+_wrapper_module = None
+def WrapperModule():
+  global _wrapper_module
+  if not _wrapper_module:
+    _wrapper_module = imp.load_source('wrapper', _MyWrapperPath())
+  return _wrapper_module
+
 def _CurrentWrapperVersion():
-  VERSION = None
-  pat = re.compile(r'^VERSION *=')
-  fd = open(_MyWrapperPath())
-  for line in fd:
-    if pat.match(line):
-      fd.close()
-      exec line
-      return VERSION
-  raise NameError, 'No VERSION in repo script'
+  return WrapperModule().VERSION
 
 def _CheckWrapperVersion(ver, repo_path):
   if not repo_path: