futility: Remove FUTIL_STATIC build rules

After CL:1210342, the 'futility_s' is no longer needed so we may drop
the related build rules. People who wants to build static version of
futility can do:
  make STATIC=true futil

BUG=chromium:765499
TEST=precq passes; make futil; make clean; make STATIC=1 futil
BRANCH=none

Change-Id: I80e83a80eaa273f09288f850c59a52494dc5bec9
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1235795
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed