Don't write tracker files for small downloads
Don't write tracker files for small downloads

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