Bug 1024715 - Create test_firefox_accounts_login to validate user authen...

...tication from Settings and FMD R=zacc,bebe
Thanks, didn't realize that.  I've removed the --timeout flags.  
I also noticed that the marionette select option seems to work inconsistently.  Without changing anything, it's failing today.  Sometimes I noticed it does that which leads me to believe there may be timing issues with this as well that I'd need to resolve:
https://github.com/rpappalax/gaia/blob/fxa-testcases-py-review/tests/python/gaia-ui-tests/gaiatest/apps/system/regions/firefox_accounts.py#L62
(Perhaps I can apply some of those 'tricks up your sleeve' here as well :)