Prevent factory reset for short passwords in CryptKeeper

Since patterns and passwords can't be shorter than 4
elements, we shouldn't count them against attempts to unlock
the device.  If we do, we risk resetting the device
due to stray input.

Bug: 18211475
Bug: 18273380

Conflicts:
        src/com/android/settings/CryptKeeper.java

Conflicts:
        src/com/android/settings/CryptKeeper.java

Change-Id: Ib329cd3383471483cda68bfac4278b17d0c09c57