flyway: fix jarDirs option

this is not a system property, but rather an argument to
org.flaywaydb.commandline.Main.main().  therefore, it must come after,
rather than before, the name of the main class.  (otherwise it's
interpreted as an argument to the VM itself.)

flyway also expects the option and value to be separated by '=', not ' '.

follows on to #76094

pkgs/development/tools/flyway/default.nix

@@ -19,8 +19,8 @@
         makeWrapper "${jre_headless}/bin/java" $out/bin/flyway \
           --add-flags "-Djava.security.egd=file:/dev/../dev/urandom" \
           --add-flags "-classpath '$out/share/flyway/lib/*:$out/share/flyway/drivers/*'" \
-          --add-flags "-DjarDirs '$out/share/flyway/jars'" \
-          --add-flags "org.flywaydb.commandline.Main"
+          --add-flags "org.flywaydb.commandline.Main" \
+          --add-flags "-jarDirs='$out/share/flyway/jars'"
       '';
       meta = with stdenv.lib; {
         description = "Evolve your Database Schema easily and reliably across all your instances";