Fix error when submitting without altname

src/jat.sh.skel

         __jat__usage "no SRC?"
         return 2
     }
+    mkdir -p "$dest" || {
+        jat__log_error "cannot write to result storage: $dest"
+        return 3
+    }
     test -n "$altname" && {
         dest="$dest/$altname"
         nhint=" as $altname"
-    }
-    mkdir -p "$(dirname "$dest")" || {
-        jat__log_error "cannot write to result storage: $dest"
-        return 3
+        mkdir -p "$(dirname "$dest")"   # needed if altname has slashes
     }
     jat__log_info "submitting result: $path$nhint"
     cp -ar "$path" "$dest"