cancel on account creation don't closes bitmask

On bitmask 0.7 rc5, during the first run of bitmask, doing the account creation if I click on cancel the window closes but bitmask keeps running without any visible window. The only way to stop bitmask here is to kill it.

Tested with the bundle on debian stable.

(from redmine: created on 2014-11-24, closed on 2015-02-27, relates #6034 (closed))