gst/elements/gsttee.c: Let's not iterate pads we're not interested in, it avoids getting sky-high refcounts on sinkpad.

Original commit message from CVS:
* gst/elements/gsttee.c: (gst_tee_do_push), (gst_tee_handle_buffer):
Let's not iterate pads we're not interested in, it avoids getting
sky-high refcounts on sinkpad.