Remove --nofast option

parallel_emerge has been stable for 4 years.

BUG=None
TEST=trybot run on chromiumos-sdk, daisy, link, gizmo.

Change-Id: I667865c19c1d7f4d0870f3a3a5da95a69f57a1ce
Reviewed-on: https://chromium-review.googlesource.com/261260
Trybot-Ready: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/sdk_lib/make_chroot.sh b/sdk_lib/make_chroot.sh
index 3840e03..417eb66 100755
--- a/sdk_lib/make_chroot.sh
+++ b/sdk_lib/make_chroot.sh
@@ -39,7 +39,6 @@
 DEFINE_boolean delete $FLAGS_FALSE "Delete an existing chroot."
 DEFINE_boolean replace $FLAGS_FALSE "Overwrite existing chroot, if any."
 DEFINE_integer jobs -1 "How many packages to build in parallel at maximum."
-DEFINE_boolean fast ${DEFAULT_FAST} "Call many emerges in parallel"
 DEFINE_string stage3_date "2010.03.09" \
   "Use the stage3 with the given date."
 DEFINE_string stage3_path "" \
@@ -80,12 +79,7 @@
   USEPKG="--getbinpkg --usepkg --with-bdeps y"
 fi
 
-# Support faster build if necessary.
-EMERGE_CMD="emerge"
-if [ "$FLAGS_fast" -eq "${FLAGS_TRUE}" ]; then
-  CHROOT_CHROMITE_DIR="${CHROOT_TRUNK_DIR}/chromite"
-  EMERGE_CMD="${CHROOT_CHROMITE_DIR}/bin/parallel_emerge"
-fi
+EMERGE_CMD="${CHROOT_TRUNK_DIR}/chromite/bin/parallel_emerge"
 
 ENTER_CHROOT_ARGS=(
   CROS_WORKON_SRCROOT="$CHROOT_TRUNK"
@@ -486,11 +480,6 @@
 else
   UPDATE_ARGS+=( --nousepkg )
 fi
-if [[ ${FLAGS_fast} -eq ${FLAGS_TRUE} ]]; then
-  UPDATE_ARGS+=( --fast )
-else
-  UPDATE_ARGS+=( --nofast )
-fi
 if [[ "${FLAGS_jobs}" -ne -1 ]]; then
   UPDATE_ARGS+=( --jobs=${FLAGS_jobs} )
 fi