Change example ControlPath to be short and unique (#69347)

Use %C as the ControlPath setting in the example config file. The old setting used %h and %r tokens, which break ansible for a few use cases, including packer provisioning, where hostname is always 127.0.0.1. %C is a hash of local host, remote host, username and port.

examples/ansible.cfg

@@ -392,7 +392,7 @@
 # In those cases, a "too long for Unix domain socket" ssh error would occur.
 #
 # Example:
-# control_path = %(directory)s/%%h-%%r
+# control_path = %(directory)s/%%C
 #control_path =
 
 # Enabling pipelining reduces the number of SSH operations required to