Revert "Discard the old CM10.2 (and older) databases on upgrade"

This reverts commit 7d5df8388b2d4eb2e4f5667cc5db09221aa9b361.

Change-Id: Ibc685128c6812484a4682828237b07e159d72579
Merge "Revert "Discard the old CM10.2 (and older) databases on upgrade"" into android-4.4