s3/libsmb: clang: Fix 'warning: Assigned value is garbage or undefined '

s3/libsmb: clang: Fix 'warning: Assigned value is garbage or undefined '

Fixes:

source3/libsmb/clireadwrite.c:1259:17: warning: Assigned value is garbage or undefined <--[clang]
        state->written += written;
                       ^  ~~~~~~~

source3/libsmb/clireadwrite.c:1722:14: warning: The left operand of '>' is a garbage value <--[clang]
        if (written > expected) {
            ~~~~~~~ ^

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
Autobuild-User(master): Gary Lockyer <gary@samba.org>
Autobuild-Date(master): Wed Aug 28 00:22:49 UTC 2019 on sn-devel-184