libobs: Make sure all code paths leave context

Should always call `gs_leave_context` after `gs_enter_context` or it
might cause a lock leave.

This commit makes sure all code paths will call `gs_leave_context` if
it called `gs_enter_context`.

Author: suogesi

libobs/obs.c

@@ -646,13 +646,16 @@ static int obs_init_video_mix(struct obs_video_info *ovi, struct obs_core_video_
 	gs_enter_context(obs->video.graphics);
 
 	if (video->gpu_conversion && !obs_init_gpu_conversion(video))
-		return OBS_VIDEO_FAIL;
+		goto fail;
 	if (!obs_init_textures(video))
-		return OBS_VIDEO_FAIL;
+		goto fail;
 
 	gs_leave_context();
 
 	return OBS_VIDEO_SUCCESS;
+fail:
+	gs_leave_context();
+	return OBS_VIDEO_FAIL;
 }
 
 struct obs_core_video_mix *obs_create_video_mix(struct obs_video_info *ovi)