nova-rootwrap: wait() for return code before exit

nova-rootwrap does not wait() for the subprocess it executes to complete before
returning its return code. This often ends up in 0 being returned regardless of
failure/success and causing unforeseen problems in Nova.

Fixes bug #928566

Change-Id: I9b6d85c747513086d0e774cb92ba403886b3283c

bin/nova-rootwrap

@@ -67,6 +67,7 @@ if __name__ == '__main__':
                                stdout=sys.stdout,
                                stderr=sys.stderr,
                                env=filtermatch.get_environment(userargs))
+        obj.wait()
         sys.exit(obj.returncode)
 
     print "Unauthorized command: %s" % ' '.join(userargs)