sr: Declare additional dependencies instead of relying on build hax

e want to include a suite of tools and symlinks with recovery.  This
was previously done with a hack in build/core/Makefile.  That is rather
unorthodox.  Instead, use LOCAL_ADDITIONAL_DEPENDENCIES to declare the
things we want to include.

See also http://review.cyanogenmod.org/74244

Change-Id: I2a00469b72bfabf989d17bafdea6cebbbc52c53e