srt: Fix GCC function type error
gstsrtobject.c: In function ‘gst_srt_object_close’: gstsrtobject.c:1036:7: error: function called through a non-compatible type [-Werror] (GDestroyNotify) g_closure_unref); /usr/include/glib-2.0/glib/gmem.h:121:8: note: in definition of macro ‘g_clear_pointer’ (destroy) (_ptr); \ ^~~~~~~ gstsrtobject.c:1038:7: error: function called through a non-compatible type [-Werror] (GDestroyNotify) g_closure_unref); /usr/include/glib-2.0/glib/gmem.h:121:8: note: in definition of macro ‘g_clear_pointer’ (destroy) (_ptr); \ ^~~~~~~ Arch Linux gcc 8.2.1 20181127 glib 2.58.2