fix: did not check correctly when errorlevel could not be collected.

bin/compose

@@ -1866,8 +1866,8 @@ launch_docker_compose() {
         err "Please re-launch your command, or switch from 'devicemapper' driver to 'overlayfs' or 'aufs'."
     fi
 
-    docker_compose_errlvl="$(cat "$docker_compose_dir/.data/errlvl")"
-    if [ -z "docker_compose_dir" ]; then
+    docker_compose_errlvl="$(cat "$docker_compose_dir/.data/errlvl" 2>/dev/null)"
+    if [ -z "$docker_compose_errlvl" ]; then
         err "Something went wrong before you could gather docker-compose errorlevel."
         return 1
     fi