Add the missing LOCAL_CFLAGS for librecovery.

The -DAB_OTA_UDPATER part was missing when separating the librecovery
module (commit 62e0bc75).

Bug: 37300957
Test: Build sailfish recovery image and sideload full OTA.
Change-Id: Idd25662f6bc812c1aca95b096802f59b051f8d63
(cherry picked from commit 25dbe171)