Update recovery snapshot version.

Update recovery snapshot version.

There is exactly one snapshot per userId - recovery agent uid pair.
Version is incremented when
1) User credential is updated
2) User unlockes phone and list of application keys was changes since
last snapshot creation.

Bug: 66499222
Test: adb shell am instrument -w -e package \
com.android.server.locksettings.recoverablekeystore \
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I6ab98fcbbb05e33958e6def644b40441cb52de6a