default port become 0 after updating to 3.26.1

[rhjdvsgsgks]

if there is no port define in nbdtab . nbd-client will try to connect address:0 rather than address:10809 . i think it may caused by #154

[athos-ribeiro]

This seems to be fixed by https://github.com/NetworkBlockDevice/nbd/commit/256f95a529f3d7128afbb890c11c2ebf4750d16f