Revert "kill recovery"

This reverts commit 650263e5d73e6a1bb00de6e1c8113a21ee2a4159.
core: Allow to disable block based OTA's

on Xiaomi Mi2, it causes that the user can't install GAPPS because
the filesystem is smaller than the partition then(users resize the syspart).

Change-Id: I1dcde9c9a212c34108629537cb8c1088a0373573

Conflicts:
	core/Makefile