Change krb5 kcmd to use getaddrinfo, and add some hooks for future ipv6

Change krb5 kcmd to use getaddrinfo, and add some hooks for future ipv6
support.

* defines.h: Include fake-addrinfo.h.
(FAI_PREFIX): Define.
(getport): Update.
* kcmd.c: Include fake-addrinfo.c.
(kcmd): Use getaddrinfo instead of gethostbyname, but only get AF_INET
addresses for now.
(k4cmd): Update argument list to getport.
(getport): Accept new argument, pointer to address family to use.  If zero, try
inet6 and then inet.
* krshd.c (doit): Update argument list to getport.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@14140 dc483132-0cff-0310-8789-dd5450dbe970