Fix mistake in crrev.com/650223005.

This was the 2nd breaking mistake in that one CL. Note: oth mistakes were not caught by unit tests or by running a bisect try job once before submitting.

BUG=425173

Review URL: https://codereview.chromium.org/662403003

Cr-Commit-Position: refs/heads/master@{#300303}

tools/auto_bisect/source_control.py

@@ -59,7 +59,7 @@ def GetRevisionList(end_revision_hash, start_revision_hash, cwd=None):
 
 def SyncToRevision(revision, sync_client=None):
   if not sync_client:
-    _, return_code = bisect_utils.RunGit(['checkout', revision])[1]
+    _, return_code = bisect_utils.RunGit(['checkout', revision])
   elif sync_client == 'gclient':
     return_code = SyncToRevisionWithGClient(revision)
   elif sync_client == 'repo':