nfs-utils: move nfssvc.c to nfsd dir and clean up linking of nfsd

rpc.nfsd is the only user of nfssvc.c, so we might as well move it
out of libnfs.a.

Also, don't link in libexport.a and libmisc.a, they aren't needed.

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