Cleanup Phone Accounts

At startup remove any already existing HFP phone accounts that may be
left over from an unclean shutdown.

Bug: 62365716
Test: Connect 2 phones, hard power cycle, turn off bt on one of the
phones, make sure that only the newly connected phone has an account via
dumpsys telecom.

Change-Id: I009b7eac176a71712257dca1961fca3b8d802dd4
(cherry picked from commit deaf590f20623295daa861edc2815dfe535ba6ef)