Allow connecting to SSL-secured servers with self-signed certificates

Adds a new configuration parameter ('check_certificate'),
which gets wired up to the rejectUnauthorized option of
tls.connect.

packages/xo-server-auth-ldap/src/index.js

@@ -26,7 +26,8 @@ class AuthLdap {
   constructor (conf) {
     const clientOpts = {
       url: conf.uri,
-      maxConnections: 5
+      maxConnections: 5,
+      tlsOptions: { }
     }
 
     {
@@ -37,6 +38,10 @@ class AuthLdap {
       }
     }
 
+    if (conf.check_certificate !== undefined) {
+      clientOpts.tlsOptions.rejectUnauthorized = conf.check_certificate
+    }
+
     const {base: searchBase} = conf
     const searchFilter = conf.filter || '(uid={{name}})'