parsers.c: parse_manifest: fixing refcount of flags
When flags was DECREF'ed, scope was referencing to the outer variable,
outside of the block.
It was in fact always NULL: the real Python object was never decref'ed.
% file replaced with directory
adding a
% should fail - would corrupt dirstate
abort: file 'a' in dirstate clashes with 'a/a'
% directory replaced with file
adding a/a
% should fail - would corrupt dirstate
abort: directory 'a' already in dirstate
% directory replaced with file
adding b/c/d
% should fail - would corrupt dirstate
abort: directory 'b' already in dirstate