Backport of "gstelement: fix deadlock in gst_element_add_pad() when >=PAUSED" into 1.20
Backport of !3635 (merged) "gstelement: fix deadlock in gst_element_add_pad() when >=PAUSED".
Commits:
- 15caeb4a gstelement: fix deadlock in gst_element_add_pad() when >=PAUSED