Fix comment in example config file.

The config file incorrectly mentions the --private-key-file flag.
Should be --private-key

examples/ansible.cfg

@@ -21,7 +21,7 @@ module_name = command
 
 remote_tmp = $HOME/.ansible/tmp
 
-# the default pattern for ansible-playbooks ("hosts:") 
+# the default pattern for ansible-playbooks ("hosts:")
 
 pattern = *
 
@@ -62,7 +62,7 @@ remote_port=22
 #remote_user=root
 
 # if set, always use this private key file for authentication, same as if passing
-# --private-key-file to ansible or ansible-playbook
+# --private-key to ansible or ansible-playbook
 
 #private_key_file=/path/to/file