(Merge 3.3) Fix posix_chflags(): return_value was uninitialized when
follow_symlinks=False whereas the fchmodat() function is not avaialble.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 86002c3..cc54790 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -2778,7 +2778,7 @@
     unsigned long flags;
     int follow_symlinks = 1;
     int result;
-    PyObject *return_value;
+    PyObject *return_value = NULL;
     static char *keywords[] = {"path", "flags", "follow_symlinks", NULL};
 
     memset(&path, 0, sizeof(path));