plugins/elements/gstmultiqueue.c: Make it so that pads are considered linked until...

plugins/elements/gstmultiqueue.c: Make it so that pads are considered linked until a buffer is pushed and discovered ...

Original commit message from CVS:
* plugins/elements/gstmultiqueue.c: (gst_multi_queue_set_property),
(gst_multi_queue_request_new_pad), (gst_single_queue_flush),
(gst_multi_queue_loop), (gst_multi_queue_sink_activate_push):
Make it so that pads are considered linked until a buffer is pushed
and discovered otherwise. This avoids problems with decodebin2 hanging
after a seek in the filesrc ! decodebin2 name=d ! fakesink d. ! fakesink
case.
Make sure we lock the multiqueue when updating the max-size properties.
Fix a crash on Solaris in a debug statement in get_request_pad that
passes a NULL string to GST_DEBUG.
* tests/check/elements/multiqueue.c: (mq_dummypad_chain),
(run_output_order_test):
Fix the test to allow the first buffer on not-linked pads to come out
of sequence while multiqueue discovers that they are not-linked.