add missing sslrootcert for native bindings

Author: wzrdtales

lib/connection-parameters.js

@@ -91,6 +91,7 @@ ConnectionParameters.prototype.getLibpqConnectionString = function (cb) {
   add(params, ssl, 'sslca')
   add(params, ssl, 'sslkey')
   add(params, ssl, 'sslcert')
+  add(params, ssl, 'sslrootcert')
 
   if (this.database) {
     params.push('dbname=' + quoteParamValue(this.database))