submodule.c: remove some of the_repository references

Commit 174d131fc9 (submodule.c: remove implicit dependency on
the_index - 2018-09-21) makes collect_changed_submodules() take a
"struct index_state *" as argument even if it's not really used. My
bad.

Instead of deleting this argument and fixing up all call sites. Let's
take this opportunity to remove some the_repository instead because
there's one or two in this function (and two more in its callback).
The callers can also get rid of some the_repository.

Noticed-by: Jeff King <peff@peff.net>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/transport.c b/transport.c
index f4ffbd9..f9343e6 100644
--- a/transport.c
+++ b/transport.c
@@ -1172,7 +1172,7 @@ int transport_push(struct transport *transport,
 					oid_array_append(&commits,
 							  &ref->new_oid);
 
-			if (!push_unpushed_submodules(&the_index,
+			if (!push_unpushed_submodules(the_repository,
 						      &commits,
 						      transport->remote,
 						      rs,
@@ -1197,7 +1197,7 @@ int transport_push(struct transport *transport,
 					oid_array_append(&commits,
 							  &ref->new_oid);
 
-			if (find_unpushed_submodules(&the_index,
+			if (find_unpushed_submodules(the_repository,
 						     &commits,
 						     transport->remote->name,
 						     &needs_pushing)) {