Nonfatal assertion in `relay_new_address_suggestion()`

Found with Chutney and travis

Warning: Bug: Tor 0.4.5.0-alpha-dev: Non-fatal assertion !(!server_mode(options)) failed in relay_address_new_suggestion at ../src/feature/relay/relay_find_addr.c:68. Stack trace: (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(+0x76b19) [0x56419a3d7b19] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(+0xacc4c) [0x56419a40dc4c] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(channel_tls_handle_cell+0x18b) [0x56419a3e504b] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(connection_handle_read+0xa3d) [0x56419a3d282d] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(do_main_loop+0xfd) [0x56419a3d8d9d] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(log_backtrace_impl+0x56) [0x56419a585ae6] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(main+0x19) [0x56419a3c3249] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(_start+0x2a) [0x56419a3c329a] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(tor_bug_occurred_+0x16c) [0x56419a580c9c] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(tor_main+0x3a) [0x56419a3c36ba] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     tor(tor_run_main+0x121d) [0x56419a3c60ed] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6(+0x1e8f8) [0x7f391805a8f8] (on Tor 0.4.5.0-alpha-dev ) Number: 5
Warning: Bug:     /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6(event_base_loop+0x53f) [0x7f391805b33f] (on Tor 0.4.5.0-alpha-dev ) Number: 5