Only attempt to delete uploaded perfdiag files if a write test ran
Only attempt to delete uploaded perfdiag files if a write test ran

craigcitro/gsutil,GoogleCloudPlatform/gsutil,dimfeld/gsutil,fishjord/gsutil,ttiurani/gsutil,mattdr/gsutil,BrandonY/gsutil,chriskuehl/gsutil-debian,dtjackson/gsutil,GoogleCloudPlatform/gsutil