winexe: Add support for connecting to a host on an alternate port

winexe: Add support for connecting to a host on an alternate port

This commit allows an optional port number to be specified after the
hostname on the winexe command line. If no port is given, it defaults
to port 445, just like it used before. Although this is probably a
pretty uncommon use-case, it allows port-forwarding the service through
a firewall to an alternate port, which can occassionally be helpful.

$ ./bin/winexe -U karl%password1 //127.0.0.1:5445 cmd.exe
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Windows\system32>

Signed-off-by: Karl Lenz <xorangekiller@gmail.com>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>