lib: Remove use of MSG_NOSIGNAL

lib: Remove use of MSG_NOSIGNAL

According to susv4 sendmsg, NOSIGAL is effective for stream-oriented sockets.
Datagram sockets won't send SIGPIPE anyway. Looking at Linux kernel sources,
this is only looked at in stream functions. I guess this is a left-over from my
tmsgd attempts, which was based on stream sockets. messaging_dgm still only
uses datagram sockets, so MSG_NOSIGNAL is not needed here.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12502

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Tue May 30 16:39:12 CEST 2017 on sn-devel-144