restore keystore reset behavior of removing master key.
otherwise after reboot keystore has is LOCKED and not UNINITIALIZED
cmds/keystore/keystore.cpp
when removing password, reset the keystore, so it doesn't remain
locked with a now bogus password.
core/java/com/android/internal/widget/LockPatternUtils.java
Change-Id: If5e0bb50b42599e9ca27a8b91d6cec12528419a1
e2afc2420d