add missing whitespace option to |git bz file|

Pull request #17 added a -w option, but failed to add the appropriate
option to the |git bz file| command.  |git bz file| fails without this
option, as other code complains about the unknown `ignore_all_spaces'
option.
Merge pull request #36 from froydnj/master

add missing whitespace option to |git bz file|