core: don't reorder drop-ins when changing properties

The drop-in order we present should actually show what we is in effect, hence
let's not reorder it when writing changes. After all, just sorting
alphabetically is going to break things, as it doesn't respect that /etc breaks
/run breaks /usr...

src/core/unit.c

@@ -3365,7 +3365,6 @@ int unit_write_drop_in(Unit *u, UnitSetPropertiesMode mode, const char *name, co
         if (r < 0)
                 return r;
 
-        strv_sort(u->dropin_paths);
         strv_uniq(u->dropin_paths);
 
         u->dropin_mtime = now(CLOCK_REALTIME);