Use ServiceSpecificException in RecoverableKeyStoreMgr

This is so we can better convey error codes to the client.

Test: adb shell am instrument -w -e package
com.android.server.locksettings.recoverablekeystore
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I02d0ed07e895d3a0297f77934830e19bb6abf43e
2 files changed