build_package.sh: Split submodule init vs update operations

In the hope that it may improve retry-ability of the update part.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Iab7f9ef402c5ac2de2e3d0fea378a4bbf19a9037
(cherry picked from commit fc1cf6be4dc68a031b53bd5d98fb0aee5e90c188)
1 file changed