text-based mount: Replace nfs_lookup() with getaddrinfo(3)

text-based mount: Replace nfs_lookup() with getaddrinfo(3)

Originally I thought it would be best to share the DNS query code
between the legacy mount code and the new text-based code, hence
the introduction of nfs_lookup().  However, it now appears we want
the text-based code to do a little more than take the first address
returned by the query.

So, let's invoke getaddrinfo(3) directly in stropts.c, and save
the returned addrinfo struct until the end of processing.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>