In a later patch, we will add new Travis Job for linux-musl.
Most of other code in this file could be reuse for that job.
Move the code to install dependencies to a common script.
Should we add new CI system that can run directly in container,
we can reuse this script for installation step.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
