cogl/trace: Fix typo

!609
3 jobs for master in 6 minutes and 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #320764
build-mutter

00:01:38

 
  Test
passed #320766
can-build-gnome-shell

00:03:30

passed #320765
test-mutter

00:05:13