Auto merge of #4317 - iKevinY:options-unit-struct, r=matklad
authorbors <bors@rust-lang.org>
Sat, 22 Jul 2017 20:53:06 +0000 (20:53 +0000)
committerbors <bors@rust-lang.org>
Sat, 22 Jul 2017 20:53:06 +0000 (20:53 +0000)
Convert Options struct into unit struct

Unit struct support was added in Docopt 0.8.1 via docopt/docopt.rs#217. Fixes #4174.


Trivial merge