gst/gst.c: Ignore EINTR when reading from the child registry pipe.

gst/gst.c: Ignore EINTR when reading from the child registry pipe.

Original commit message from CVS:
* gst/gst.c: (ensure_current_registry_forking):
Ignore EINTR when reading from the child registry pipe.
Explicitly ignore the return value from close, since it makes no
difference.
* gst/gstminiobject.c: (gst_mini_object_ref),
(gst_mini_object_unref):
When debugging refcounts, check GST_IS_MINI_OBJECT and warn.
* gst/gstregistry.c: (_priv_gst_registry_remove_cache_plugins):
When removing cached plugins, remove their features too, so they're
not visible after they've disappeared.
* gst/gstutils.c: (prepare_link_maybe_ghosting):
In the unlikely case that we are linking pads with no parents, don't
crash trying to get the non-existent parent bin.
* gst/parse/grammar.y:
Output debug in the PIPELINE category