Change how we use provisioning url so post works

Needed to do an http post instead of a get for one carrier.
Do this by putting an auto-submitting form in the data to be
interpreted as a html doc by the browser.  The ACTION_VIEW
intent only works on http uri, but by specifying ACTION_MAIN/
CATEGORY_APP_BROWSER we could use data:text/html.

bug:11168810
Change-Id: Ifd33e1c3c7f9f40b6add39e446e6a7d7cde22549