remove monitor_keys_example file

remove monitor_keys_example file

This file is not needed, if you want to generate a key you can run:

python -c "import os ; import struct ; import time; import base64 ; key
= os.urandom(16) ; header =
struct.pack('<hiih',1,int(time.time()),0,len(key)) ;
print(base64.b64encode(header + key).decode())"

Signed-off-by: Sébastien Han <seb@redhat.com>