archive-source.sh: Clone the submodules locally

We cloned the QEMU repository from the local storage. Since the
submodules are also available there, clone them too. This is
quicker and reduce network use.
Signed-off-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
[AJB: incorporated review suggestions from danpb]
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>

scripts/archive-source.sh

@@ -38,6 +38,13 @@ else
 fi
 git clone --shared . "$vroot_dir"
 test $? -ne 0 && error "failed to clone into '$vroot_dir'"
+for sm in $submodules; do
+    if test -d "$sm/.git"
+    then
+       git clone --shared "$sm" "$vroot_dir/$sm"
+       test $? -ne 0 && error "failed to clone submodule $sm"
+    fi
+done
 
 cd "$vroot_dir"
 test $? -ne 0 && error "failed to change into '$vroot_dir'"