Fix bug ID on a GPU driver bug workaround entry.

Note that the CL that's merged back to M73 already had the correct bug ID.

BUG=932879
TEST=bots
TBR=sunnyps@chromium.org
NOTRY=true

Change-Id: I7f647b56eda402ee2e383f35f867e0ba16664c90
Reviewed-on: https://chromium-review.googlesource.com/c/1490398
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635750}

gpu/config/gpu_driver_bug_list.json

@@ -3170,7 +3170,7 @@
     },
     {
       "id": 294,
-      "cr_bugs": [931399],
+      "cr_bugs": [932879],
       "description": "Hardware overlays result in black videos on non-Intel GPUs",
       "os": {
         "type": "win"