libnsm.a: Move the sm_inter XDR pieces to libnsm.a

Clean up: Move the .x file and the generated C source for NSM to
libnsm.a, echoing the architecture of mountd and exportfs.  This makes
the NSM protocol definitions, data types, and XDR routines available
to be shared across nfs-utils.

This simplifies the addition of other NSM-related code (for example
for testing or providing clustering support), and also provides
public data type definitions that can be used to make sense of the
contents of statd's on-disk database.

Because sim_sm_inter.x still resides in utils/statd, I've left some
rpcgen build magic in utils/statd/Makefile.am.

This is an internal organization change only.  This patch should not
affect code behavior in any way.

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