Revert "Run stop b2g and start b2g with 'adb root' privs"

This reverts commit cedf51858c403f3b8c9db9ce76758a51617c8cd1.
Merge pull request #1211 from zacc/revert_root_privs

Revert "Run stop b2g and start b2g with 'adb root' privs"