Revert "ota: Make sure we don't install on top of an incompatible system"

We can't use calendar since since some gapps packages replace it.

This reverts commit a0c756677814e81f63b56b30cd0831c543154520.

Change-Id: Ic46589e47728804f2d89051f4aecf355f37d85a0
Merge remote-tracking branch 'CyanogenMod/cm-11.0' into cm-11.0