Storage options cannot be specified for s3

[garethbridger]

Attempting to specify storage options for s3 results in the following error:

/usr/local/bin/whisper-backup -b mybucket backup s3 region=eu-west-1
Traceback (most recent call last):
  File "/usr/local/bin/whisper-backup", line 11, in <module>
    load_entry_point('whisper-backup==0.3.0', 'console_scripts', 'whisper-backup')()
  File "/usr/local/lib/python2.7/dist-packages/whisper_backup-0.3.0-py2.7.egg/whisperbackup/whisperbackup.py", line 526, in main
    script.store = storageBackend(script)
  File "/usr/local/lib/python2.7/dist-packages/whisper_backup-0.3.0-py2.7.egg/whisperbackup/whisperbackup.py", line 86, in storageBackend
    gcsargs[fields[0]] = fields[1]
UnboundLocalError: local variable 'gcsargs' referenced before assignment

This looks to be caused by a minor copypasta

[garethbridger]

Opened pull request: #24

[Jack Neely]

Awesome! Thank you! Merged.