Remove UID checks from LockPatternUtils

The UID checks should be unnecessary because LockPatternUtils already relies
on system permission checks in Settings, LockSettings, DevicePolicyManager
and Keystore.  These checks should already catch illegal operations.

This was interfering with the stand-alone test app for keyguard.

Change-Id: I2da2a729ca29feae9e962c2e360ec47490bcbbf0