ports/checkportstree: syntax tweak for pushd/popd errors caused by find duplicates

ports/checkportstree

@@ -64,8 +64,9 @@ outdated_pkg() {
 outdated() {
     local prt otd
     for prt in $(cat $ALL_PKGS); do
-        pushd $(find -L $PORTS_DIR -maxdepth 2 -name $prt -type d) > /dev/null
-        otd="$otd  $(outdated_pkg)"
+        pushd */$prt > /dev/null
+        O="$(outdated_pkg)"
+        [ -n "$O" ] && otd="$otd  $O"
         popd > /dev/null
     done
     print_result "Outdated" "$otd"