Fix the --project flag.

$ push -h
Usage of push:
  -alsologtostderr=false: log to standard error as well as files
  -config_filename="skiapush.conf": Config filename.
  -graphite_server="skia-monitoring:2003": Where is Graphite metrics ingestion server running.
  -local=false: Running locally if true. As opposed to in production.
  -log_backtrace_at=:0: when logging hits line file:N, emit a stack trace
  -log_dir="": If non-empty, write log files in this directory
  -logtostderr=false: log to standard error instead of files
  -oauth=true: Run through the OAuth 2.0 flow on startup, otherwise use a GCE service account.
  -oauth_cache_file="google_storage_token.data": Path to the file where to cache cache the oauth credentials.
  -port=":8000": HTTP service address (e.g., ':8000')
  -project="google.com:skia-buildbots": The Google Compute Engine project.
  -resources_dir="": The directory to find templates, JS, and CSS files. If blank the current directory will be used.
  -stderrthreshold=0: logs at or above this threshold go to stderr
  -v=0: log level for V logs
  -vmodule=: comma-separated list of pattern=N settings for file-filtered logging
  -zone="us-central1-f": The Google Compute Engine zone.

BUG=skia:

Review URL: https://codereview.chromium.org/802373002
Have pull be more robust to package names.

Push will write package names that look like "{appname}/",
and pull should ignore them.

BUG=skia:

Review URL: https://codereview.chromium.org/803933004