updating sleep to allow nil arguments

lib/rex.rb

@@ -91,7 +91,7 @@ require 'rex/platforms'
 
 # Overload the Kernel.sleep() function to be thread-safe
 Kernel.class_eval("
-	def sleep(seconds)
+	def sleep(seconds=nil)
 		Rex::ThreadSafe.sleep(seconds)
 	end
 ")

lib/rex/sync/thread_safe.rb

@@ -72,7 +72,7 @@ module ThreadSafe
 	# Simulates a sleep operation by selecting on nil until a timeout period
 	# expires.
 	#
-	def self.sleep(seconds)
+	def self.sleep(seconds=nil)
 		self.select(nil, nil, nil, seconds)
 
 		seconds