nfs-utils: convert nfssvc_setfds to use getaddrinfo

Convert nfssvc_setfds to use getaddrinfo. Change the args that it takes
and fix up nfssvc function to pass in the proper args. The things that
nfssvc has to do to call the new nfssvc_setfds is a little cumbersome
for now, but that will eventually be cleaned up in a later patch.

nfs-utils: break up the nfssvc interface

Currently, the only public interface to the routines in nfssvc.c is
nfssvc(). This means that we do an awful lot of work after closing
stderr that could be done while it's still available.

Add prototypes to the header so that more functions in nfssvc.c can be
called individually, and change the nfsd program to call those routines
individually.

Signed-off-by: Steve Dickson <steved@redhat.com>