fix meterp sessions getting initialized improperly, fix msf> prompt in exploit context after color cmd

git-svn-id: file:///home/svn/framework3/trunk@7449 4d416f70-5f16-0410-b530-b9f4589650da

lib/msf/ui/console/command_dispatcher/core.rb

@@ -124,7 +124,7 @@ class Core
 			print_line("Enable or disable color output.")
 			return
 		end
-		driver.update_prompt('')
+		driver.update_prompt
 	end
 
 	def cmd_resource(*args)

lib/rex/ui/text/dispatcher_shell.rb

@@ -183,7 +183,8 @@ module DispatcherShell
 		found     = false
 		error     = false
 
-		output.reset_color
+		# If output is disabled output will be nil
+		output.reset_color if (output)
 
 		if (method)
 			entries = dispatcher_stack.length

lib/rex/ui/text/output.rb

@@ -39,7 +39,8 @@ class Output < Rex::Ui::Output
 		@config[:color] = :auto
 	end
 
-	def update_prompt(prompt)
+	def update_prompt(prompt = nil)
+		return if prompt.nil?
 		substitute_colors(prompt)
 	end