Update submodule url unequivocally.

crup-runner.sh

 #!/bin/bash
 
 update_toplevel () {
   # Don't "pull" if checkout is not on a named branch
   if test "$2" = "pull" && ( ! git symbolic-ref HEAD >/dev/null 2>/dev/null ); then
     first_args="$1 fetch"
   else
     first_args="$1 $2"
   fi
   shift 2
@@ skipping 22 matching lines @@
     git config target.os "$target_os"
   fi
 }
 
 update_submodule_url () {
   # If the submodule's URL in .gitmodules has changed, propagate the new
   # new URL down.  This is the same as `git submodule sync`, but we do it
   # this way because `git submodule sync` is absurdly slow.
   new_url=$(git config -f .gitmodules "submodule.$1.url" 2>/dev/null)
   old_url=$(git config "submodule.$1.url" 2>/dev/null)
-  if [ -n "$old_url" -a "$new_url" != "$old_url" ]; then
+  if [ "$new_url" != "$old_url" ]; then
     git config "submodule.$1.url" "$new_url"
     if [ -e "$1"/.git ]; then
       ( cd $submod && git config remote.origin.url "$new_url" )
     fi
   fi
 }
 
 process_submodule () {
   # Check whether this submodule should be ignored or updated.
   # If it's a new submodule, match the os specified in .gitmodules against
@@ skipping 65 matching lines @@
   submodule="${1#*/}"
   echo "[$solution] updating $submodule"
   git submodule update --recursive --quiet "$submodule" |
   ( grep -v '^Skipping submodule' || true ) | sed "s|^|[$1] |g" 2>/dev/null
   status=$?
   if [ "$status" -ne "0" ]; then
     echo "[$solution] FAILED to update $submodule"
   fi
 fi
 exit $status