gst/gstbin.c: The message src can be NULL, don't try to print the object names in...

gst/gstbin.c: The message src can be NULL, don't try to print the object names in that case.

Original commit message from CVS:
* gst/gstbin.c: (gst_bin_remove_func), (update_degree),
(gst_bin_handle_message_func):
The message src can be NULL, don't try to print the object names in that
case.
* libs/gst/base/gstbasesink.c: (gst_base_sink_pad_activate):
Add some more debug info.
* tests/check/pipelines/simple-launch-lines.c: (run_pipeline),
(GST_START_TEST):
Add some debug.
Fix the test, pull based sinks go ASYNC to PAUSED, just like other
scheduling modes.