manager: don't try to minimize transaction when using isolate

We should not avoid stopping services when using isolate, since that
kinda defeats the point of it.

http://bugzilla.redhat.com/show_bug.cgi?id=627014

src/manager.c

@@ -1226,7 +1226,8 @@ static int transaction_activate(Manager *m, JobMode mode, DBusError *e) {
         /* Second step: Try not to stop any running services if
          * we don't have to. Don't try to reverse running
          * jobs if we don't have to. */
-        transaction_minimize_impact(m);
+        if (mode != JOB_ISOLATE)
+                transaction_minimize_impact(m);
 
         /* Third step: Drop redundant jobs */
         transaction_drop_redundant(m);