Refactor: CanCan::Rule#matches_conditions_hash?

The If-Castle is not so dark now.

CodeClimate reports +11 to summary GPA

[Before][1]: 2.47 GPA, method complexity [44][2]
[After][3]:  2.58 GPA, method complexity 0

[1]: https://codeclimate.com/github/CanCanCommunity/cancancan/compare/develop
[2]: https://codeclimate.com/github/CanCanCommunity/cancancan/CanCan::Rule
[3]: https://codeclimate.com/github/vrybas/cancancan/compare/refactoring-matches-conditions-hash-method