rtpjitterbuffer: Clear clock master before unreffing

Make sure to clear any master clock on the media_clock
before unreffing it to release the timer callback that's
updating the clock and keeping it reffed.
20 jobs for rtpjitterbuffer-clear-clock-master in 47 minutes and 36 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Preparation
passed #361976
gst indent

00:00:28

passed #361975
manifest

00:00:20

 
  Build
passed #361982
build cerbero android universal

00:12:21

passed #361983
build cerbero cross win32

00:14:25

passed #361984
build cerbero cross win64

00:06:32

passed #361981
build cerbero fedora x86_64

00:12:50

passed #361985
gst-macos-10.14
build cerbero macos x86_64

00:08:52

passed #361977
build fedora x86_64

00:13:44

passed #361978
build nodebug fedora x86_64

00:13:01

passed #361979
build static fedora x86_64

00:17:59

passed #361980
build static nodebug fedora x86_64

00:15:41

 
  Test
passed #362337
check fedora

00:05:31

passed #361987
integration testsuites fedora

00:14:41

passed #361989
valgrind bad

00:08:16

passed #361990
valgrind ges

00:06:05

passed #362338
valgrind good

00:07:43

failed #361986
check fedora

00:06:13

failed #361988
valgrind good

00:23:12

 
  Integrate
passed #361991
android universal examples

00:06:36

passed #361992
documentation

00:02:45