Duplicate widget definition on BaseLoggedInPage

[mshriver]

As highlighted by discussion in #544, there are duplicate widgets defined in BaseLoggedInPage.

https://github.com/SatelliteQE/airgun/blob/master/airgun/views/common.py#L42

This should be cleaned up, with only account_menu widget defined, as this accurately describes the UI element.

Robottelo should be updated accordingly.