make_factory_toolkit: Set host_based flag to boolean type

Instead of defining it as a string, we should use DEFINE_boolean.

BUG=none
TEST=Run the script with and without --host_based. Check the resulting
toolkit shellball.

Change-Id: Ib6a737215b9ab21f3f3e3976db5f9c6622cdbb01
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/211252
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/make_factory_toolkit.sh b/make_factory_toolkit.sh
index b197823..63412c6 100755
--- a/make_factory_toolkit.sh
+++ b/make_factory_toolkit.sh
@@ -19,7 +19,7 @@
 DEFINE_string output_dir "" "Path to the folder to store the factory toolkit."
 DEFINE_string version "" \
   "The version tag to be included in the identification string."
-DEFINE_string host_based "0" \
+DEFINE_boolean host_based "${FLAGS_FALSE}" \
   "Whether to build a host-based toolkit."
 
 cleanup() {
@@ -89,7 +89,7 @@
   ln -s "${version_tag}" "${temp_pack_root}/VERSION"
 
   # Determine whether to use host-based or monolithic goofy
-  if [[ "${FLAGS_host_based}" -ne "0" ]]; then
+  if [[ "${FLAGS_host_based}" -eq "${FLAGS_TRUE}" ]]; then
     local goofy_link_dst=goofy_split
   else
     local goofy_link_dst=goofy_monolithic