need to abort threads on exception so that things don't hang mystical…

…ly when using the gateway

lib/capistrano/configuration/connections.rb

@@ -22,6 +22,7 @@ def connect_to(server)
 
       class GatewayConnectionFactory #:nodoc:
         def initialize(gateway, options)
+          Thread.abort_on_exception = true
           server = ServerDefinition.new(gateway)
           @gateway = Net::SSH::Gateway.new(server.host, server.user || ServerDefinition.default_user, server.options)
           @options = options