vold: Clean up warnings

 * Clean up all the dead code and get rid of all warnings

Change-Id: I8101b6314012a39e8e3a9b9b9aa8f4841b4c430d
Do not show disk errors if they are expected.

An error shows up during boot if vold disk has different majors.
On some devices this is expected and set in config, so do not
confuse users and skip the error (as it ain't one)
Bonus: Better log for duplicate state. It was useless...

Change-Id: Ibc047729432e2f6746a9439b828d1443951ade1f