fetcher: Remove "sending_messages" hash table
fetcher: Remove "sending_messages" hash table

Vestige of ostree_fetcher_query_state_text(), removed last year.

gatispaeglis/ostree,gatispaeglis/ostree,gatispaeglis/ostree,gatispaeglis/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree,gatispaeglis/ostree,gatispaeglis/ostree