backend CHANGE dummy hostkey checking

consider all hostkeys valid until a process of verifying hostkeys by
users is implemented
diff --git a/backend/connections.py b/backend/connections.py
index 596d1a5..977974f 100644
--- a/backend/connections.py
+++ b/backend/connections.py
@@ -9,7 +9,6 @@
 
 from liberouterapi import auth
 from flask import request
-import libyang as ly
 import netconf2 as nc
 
 from .inventory import INVENTORY
@@ -19,6 +18,10 @@
 
 sessions = {}
 
+def hostkey_check(hostname, state, keytype, hexa, priv):
+	# TODO real check
+	return True
+
 @auth.required()
 def connect():
 	session = auth.lookup(request.headers.get('Authorization', None))
@@ -41,6 +44,7 @@
 	nc.setSearchpath(path)
 
 	ssh = nc.SSH(device['username'], password=device['password'])
+	ssh.setAuthHostkeyCheckClb(hostkey_check)
 	try:
 		session = nc.Session(device['hostname'], device['port'], ssh)
 	except Exception as e: