releasetools: Remove recovery build remnants

This breaks "classic" (not blockmode) OTA ZIP generation

Generating recovery patches was originally removed in 84a770ad

5.0 added some additional related stuff - remove those remnants.

Change-Id: Idfb5540bd0c77b0cf69ac4290753fffc0c17f733
Merge "releasetools: Remove recovery build remnants" into lp5.0