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
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_system_vold into cm-11.0