Change interface to bb_lookup_host, dont try and set port inside this

Change interface to bb_lookup_host, dont try and set port inside this
function as there is no gracefull way of handling failures.
Rename bb_getport to bb_lookup_port, allow a default port to be
specified so it always returns a correct value.
Modify ftpgetput/rdate/wget to use the new interface.
wget/rdate now use etc/services with a falback default value.