gst/gstbin.c: Always change the state of a NO_PREROLL element even if it has ASYNC elements inside (in case of a bin).

Original commit message from CVS:
* gst/gstbin.c: (gst_bin_element_set_state):
Always change the state of a NO_PREROLL element even if it has ASYNC
elements inside (in case of a bin).
* tests/check/generic/sinks.c: (GST_START_TEST), (gst_sinks_suite):
Unit test for this case.