lib/replace: Remove #undef TCP_NODELAY

lib/replace: Remove #undef TCP_NODELAY

A duplicate define warning is better than not defining this at all.

Similar to a patch Torsten Werner submitted to the Samba Bugzilla in
2005.

Not tested on HP-UX

reverts fc84e916f628b4fb6f6667ad45d0ced0e9134b23 that was still present in
the new copy of nis.h created in c29d087e1ea4c92717ef86e372fe80f410580fdc

BUG: https://bugzilla.samba.org/show_bug.cgi?id=2406
BUG: https://bugzilla.samba.org/show_bug.cgi?id=2140

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Tue Jun 18 06:47:05 UTC 2019 on sn-devel-184