virtualcam-module: Don't send frames on initial pause

Sending frames on initial pause seems to cause an odd crash on
subsequent frame calls.

(Note by author: I do not know why the crash happened because code
beyond OBS is a proprietary black box. I suspect it's just a bug in
WebRTC or something, but I can't know for sure. This is incredibly
frustrating. But at least this particular crash seems to be fixed.
...for now.)

plugins/win-dshow/virtualcam-module/virtualcam-filter.cpp

@@ -138,7 +138,7 @@ STDMETHODIMP VCamFilter::Pause()
 		return hr;
 	}
 
-	os_atomic_set_bool(&active, true);
+	os_atomic_set_bool(&active, false);
 	SetEvent(thread_start);
 	return S_OK;
 }