Handle the old wait/nowait shift behavior.

The old msfupdate would shift the first argument off the stack
regardless what it was. We have two possible candaidates now, wait and
nowait. Shouldn't be any others.

[SeeRM rapid7#7297]

msfupdate

@@ -28,8 +28,11 @@ end
 
 @args.each_with_index do |arg,i|
 	case arg
-	when "wait"
+	# Handle the old wait/nowait argument behavior
+	when "wait", "nowait"
 		@wait_index = i
+		@actually_wait = (arg == "wait")
+	# Handle passing a config-dir especially
 	when /--config-dir/
 		# Spaces in the directory should be fine since this whole thing is passed
 		# as a single argument via the multi-arg syntax for system() below.
@@ -54,7 +57,7 @@ else
 	system("svn", "update", *@args)
 end
 
-if @wait_index
+if @actually_wait
 	$stderr.puts ""
 	$stderr.puts "[*] Please hit enter to exit"
 	$stderr.puts ""