Update ms12_020_maxchannelids.rb

ms12_020_maxchannelids.rb produces a call stack when the connection is timed out. 

To reproduct, just run the module against a system having no RDP enabled.
Update ms12_020_maxchannelids.rb

ms12_020_maxchannelids.rb produces a call stack when the connection is timed out. 

To reproduct, just run the module against a system having no RDP enabled.
using theirs
Merge branch 'master' of https://github.com/darknight007/metasploit-framework

Conflicts:
	modules/auxiliary/dos/windows/rdp/ms12_020_maxchannelids.rb
modified ms12-020 module to resolve stack print
ms12-020 stack print resolve
Land #2509, @darknight007's patch to handle ms12_020_maxchannelids exceptions while connecting