Fixed namespace issue
Summary:
PhabricatorAPIException inherits from \RuntimeException,
not from Nasqueron\Notifications\Phabricator\RuntimeException.
This issue has been noticed running phpDox:
[phpdox] [31.12.2015 - 23:48:38] -
Nasqueron\Notifications\Phabricator\PhabricatorAPIException
(missing Nasqueron\Notifications\Phabricator\RuntimeException)
Test Plan: trivial
Reviewers: dereckson
Differential Revision: http://devcentral.nasqueron.org/D144