add -use_find_cache

for $(shell if [ -d $1 ] ; then cd $1 ; find ./ -not -name '.*' -and -type f -and -not -type l ; fi),
it will look up find cache instead of invoking shell command.

% time ./repo/android.sh kati -c >/dev/null
find: `dummy': No such file or directory
find: `dummy': No such file or directory
fatal: Not a git repository: 'packages/apps/Camera2/.git'
./repo/android.sh kati -c > /dev/null  34.08s user 41.16s system 131% cpu 57.423 total

% time ./repo/android.sh kati -c -use_find_cache >/dev/null
find: `dummy': No such file or directory
find: `dummy': No such file or directory
fatal: Not a git repository: 'packages/apps/Camera2/.git'
./repo/android.sh kati -c -use_find_cache > /dev/null  35.82s user 33.25s system 142% cpu 48.495 total
3 files changed