Update recovery_keys.c

Builds fail without this commit. Tested and compiled successfully.
CM Commit in android_bootable_recovery causing issue:- http://review.cyanogenmod.org/#/c/62724/
Fixed as in 19100G: https://github.com/CyanogenMod/android_device_samsung_i9100g/commit/9c5d29234a68312fb838c4314db4d2fa757403e0