Update mStartPage to make language selection work on other pages

We should offer language selection on any start page such as
decrypt or system read only. However, if the mStartPage variable
was not being updated properly so selecting a different language
was dumping the user back on either the decrypt prompt or the
system read only page. This patch set fixes the problem and places
the user back on the proper page when they choose a new language.

Change-Id: I5153d3b9525d8c93d3863f4b17ecf55b5209e3c7