Fix cut'n'paste error: leave the CriticalSection not enter it again
(found by smatch).

diff --git a/dlls/quartz/filtergraph.c b/dlls/quartz/filtergraph.c
index 4c3f6c0..edba57e 100644
--- a/dlls/quartz/filtergraph.c
+++ b/dlls/quartz/filtergraph.c
@@ -2402,7 +2402,7 @@
 	    PostMessageW(This->notif.hWnd, This->notif.msg, 0, This->notif.instance);
     }
 
-    EnterCriticalSection(&This->evqueue.msg_crst);
+    LeaveCriticalSection(&This->evqueue.msg_crst);
     return S_OK;
 }