Delete an Activation key which has registered systems
Merge pull request #1602 from sghai/ak-test

Delete an activation key which has registered system
Fix a buggy dict update

Method `update_dictionary` behaves almost exactly like the `update` method from
the standard library. Consider these two lines of code:

    d1.update(d2)
    update_dictionary(d1, d2)

In the first case, `d1` will receive all keys from `d2`:

    >>> d1 = {1: 10, 2: 20}
    >>> d2 = {2: 25, 3: 30}
    >>> d1.update(d2)
    >>> d1
    {1: 10, 2: 25, 3: 30}

In the second case, `d1` will receive only intersecting keys from `d2`:

    >>> d1 = {1: 10, 2: 20}
    >>> d2 = {2: 25, 3: 30}
    >>> update_dictionary(d1, d2)
    >>> helpers.update_dictionary(d1, d2)
    {1: 10, 2: 25}

Fix a bug in `robottelo.ui.factory` where the two dict update methods are used,
one after the other.