don't throw away the postgres client's password

broken by tgriesser/knex#390

lib/dialects/postgres/index.js

@@ -108,6 +108,7 @@ Client_PG.prototype.acquireRawConnection = Promise.method(function(callback) {
     database : connection.connectionParameters.database,
     port : connection.connectionParameters.port,
     host : connection.connectionParameters.host,
+    password : connection.connectionParameters.password
   };
 
   return new Promise(function(resolver, rejecter) {