Fix sub manifest handling

Also fixes some typos

Change-Id: Id2ba5834ba3a74ed3f29c36d2c0030737dc63e35
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/334579


Tested-by: LaMont Jones <lamontjones@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>