Issue: 2569 - Fix phase2 authentication type being cleared.

When the phase2 authentication type is saved, it gets the string
'auth=' prepended to it.  This string is reloaded when the settings
are brought up, and it is used to position the preference pulldown
to the correct index, the entries of which do not have that string
added to them.  This strips the 'auth=' string when reloading
the settings for editing.

Change-Id: Id8c4225735f26d4295cdeda258be355b48123187