core/job: never consider reload jobs redundant

Follow-up for 656bbffc6c

The commit reworked job merging logic so that reload jobs
won't get merged. However, they might get dropped from
transaction due to being deemed redundant, i.e. way before
it even hits job_install(). Let's make sure reload jobs
are always kept during transaction construction stage, too.

src/core/job.c

@@ -448,9 +448,8 @@ bool job_type_is_redundant(JobType a, UnitActiveState b) {
                 return IN_SET(b, UNIT_ACTIVE, UNIT_RELOADING, UNIT_REFRESHING);
 
         case JOB_RELOAD:
-                return
-                        b == UNIT_RELOADING;
-
+                /* Reload jobs are never consider redundant/duplicate. Refer jobs_may_late_merge() for
+                 * a detailed justification. */
         case JOB_RESTART:
                 /* Restart jobs must always be kept.
                  *