s3: lib, s3: modules: Fix compilation on Solaris.

s3: lib, s3: modules: Fix compilation on Solaris.

Based on work from YOUZHONG YANG <youzhong@gmail.com>.
Code needs fixing when HAVE_STRUCT_MSGHDR_MSG_CONTROL is
not defined. Also Solaris doesn't have msg_flags field
(which we set to zero anyway, so if we initialize
the entire struct to zero, we never need to refer to it).

https://bugzilla.samba.org/show_bug.cgi?id=10849

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Mon Oct  6 12:33:36 CEST 2014 on sn-devel-104

(cherry picked from commit 57bcb8055eb3e15c4ce7bcdeeef7efed175ed347)