quartz: Fix testing of HRESULT types with not operator instead of comparing against S_OK.

This makes it more obvious what the code is doing.
diff --git a/dlls/quartz/control.c b/dlls/quartz/control.c
index e719831..a2db24b 100644
--- a/dlls/quartz/control.c
+++ b/dlls/quartz/control.c
@@ -254,7 +254,7 @@
                     IMediaSeeking *seek = NULL;
 
                     hr_local = IPin_QueryInterface( connected, &IID_IMediaSeeking, (void**)&seek );
-                    if (!hr_local)
+                    if (hr_local == S_OK)
                     {
                         foundend = TRUE;
                         if (crit_sect)