Disable default sorting on MSSQL results

When printing output using the `mssql_print_reply`, the output gets
sorted by default by the first column. This can distort the output,
especially when the row order is crucial like in case of executing
external commands with `mssql_xpcmdshell`.

This patch disables sorting by initializing Rex::Ui::Text::Table
with SortIndex = -1.

lib/msf/core/exploit/mssql.rb

@@ -694,9 +694,10 @@ module Exploit::Remote::MSSQL
     if(info[:rows] and not info[:rows].empty?)
 
       tbl = Rex::Ui::Text::Table.new(
-        'Indent'  => 1,
-        'Header'  => "",
-        'Columns' => info[:colnames]
+        'Indent'    => 1,
+        'Header'    => "",
+        'Columns'   => info[:colnames],
+        'SortIndex' => -1
       )
 
       info[:rows].each do |row|