waylandsink: Add missing wl_registry global_remove handler

Fix crash when getting global_remove event:
[1780138.337] wl_registry@2.global_remove(22)
listener function for opcode 1 of wl_registry is NULL
Aborted

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
24 jobs for global_remove in 60 minutes and 25 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Preparation
passed #831911
gst indent

00:00:31

passed #831910
manifest

00:00:21

 
  Build
passed #831921
build cerbero cross-android universal

00:14:35

manual #831925
gst-ios-12.2 allowed to fail manual
build cerbero cross-ios universal
passed #831922
build cerbero cross win32

00:07:23

passed #831923
build cerbero cross win64

00:05:24

passed #831920
build cerbero fedora x86_64

00:06:09

passed #831924
gst-macos-10.14
build cerbero macos x86_64

00:06:56

passed #831916
build clang fedora x86_64

00:05:58

passed #831912
build fedora x86_64

00:05:55

passed #831919
docker windows 1607
build msys2

00:11:57

passed #831913
build nodebug fedora x86_64

00:04:25

passed #831914
build static fedora x86_64

00:10:10

passed #831915
build static nodebug fedora x86_64

00:04:09

passed #831917
docker windows 1607
build vs2017 amd64

00:09:56

passed #831918
docker windows 1607
build vs2017 x86

00:10:25

 
  Test
passed #831926
check fedora

00:04:11

passed #839948
integration testsuites fedora

00:39:30

passed #831928
valgrind bad

00:12:51

failed #839588
integration testsuites fedora

00:40:53

failed #831927
integration testsuites fedora

01:00:01

 
  Integrate
passed #831929
cross-android universal examples

00:05:53

manual #831931
gst-ios-12.2 allowed to fail manual
cross-ios universal examples
passed #831930
documentation

00:04:24