correct invocation of launchctl

When I executed `launchctl limit maxfiles 1024 2048` , my entire system would become unusable, as all of the sudden no process could use any file anymore, reporting that the max file limit was reached.
Only a hard reboot could fix the problem, which fortunately revealed that the configuration was not saved.

The change I made *should* remedy the issue, even though I didn't test it.
Therefore I hope you can revise the documentation to be sure nothing bad happens.

# Meta

Tested on OSX 10.11.2

docsite/rst/intro_installation.rst

@@ -52,7 +52,7 @@ This includes Red Hat, Debian, CentOS, OS X, any of the BSDs, and so on.
 .. note::
 
     As of 2.0 ansible uses a few more file handles to manage its forks, OS X has a very low setting so if you want to use 15 or more forks
-    you'll need to raise the ulimit, like so ``sudo launchctl limit maxfiles 1024 2048``. Or just any time you see a "Too many open files" error.
+    you'll need to raise the ulimit, like so ``sudo launchctl limit maxfiles 1024 unlimited``. Or just any time you see a "Too many open files" error.
 
 
 .. _managed_node_requirements: