gdb: fix stale references to so_list Adjust some comments and function names that refer to the ancient so_list type. Update some other stale comments in solib-svr4.c at the same time. Change-Id: Ia42efa6554d0cc6abb4183b6bffc96c6358c5735 Reviewed-By: Guinevere Larsen <guinevere@redhat.com>