devel/upload: Fix permissions for installed directories

Permissions for the directories created during install depended on the
umask of the user running the script.  Now umask is reset inside the script
to remove such dependency.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
(cherry picked from commit 0f796800)