gst/gstmessage.*: Also carry the clock in question.

gst/gstmessage.*: Also carry the clock in question.

Original commit message from CVS:
* gst/gstmessage.c: (gst_message_new_error),
(gst_message_new_warning), (gst_message_new_tag),
(gst_message_new_state_changed), (gst_message_new_clock_provide),
(gst_message_new_clock_lost), (gst_message_new_new_clock),
(gst_message_new_segment_start), (gst_message_new_segment_done),
(gst_message_parse_state_changed),
(gst_message_parse_clock_provide), (gst_message_parse_clock_lost),
(gst_message_parse_new_clock):
* gst/gstmessage.h:
Also carry the clock in question.