fetcher: Remove message_to_request table
fetcher: Remove message_to_request table

Does not appear to be needed, no lookups on the table.

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