cli/scripts: more cros_build_lib.run API migrations

BUG=b:187789262
TEST=CQ passes

Change-Id: Idcc78ccfe14fdbae89ae7573d6e78036bdacf8ad
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3738519
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Ram Chandrasekar <rchandrasekar@google.com>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Ram Chandrasekar <rchandrasekar@google.com>
diff --git a/scripts/cros_sdk_unittest.py b/scripts/cros_sdk_unittest.py
index 85415e7..5e43307 100644
--- a/scripts/cros_sdk_unittest.py
+++ b/scripts/cros_sdk_unittest.py
@@ -120,7 +120,7 @@
     except cros_build_lib.RunCommandError as e:
       raise SystemExit('Running %r failed!: %s' % (cmd, e))
 
-    return result.returncode, result.output
+    return result.returncode, result.stdout
 
   def testSnapshotsRequireImage(self):
     code, output = self._crosSdk(['--snapshot-list', '--nouse-image'])