pg-connection-string: avoid clobbering port from queryparams

If the connection string is something like:
    postgresql://demo:password@/postgres?host=localhost&port=26258

Then the port from the query parameters should be used. Previously, the
parsing function would end up with a null port, and the default port
would end up being used by the connecetion package.

Author: rafiss

packages/pg-connection-string/index.js

@@ -31,7 +31,6 @@ function parse(str) {
   config.user = auth[0]
   config.password = auth.splice(1).join(':')
 
-  config.port = result.port
   if (result.protocol == 'socket:') {
     config.host = decodeURI(result.pathname)
     config.database = result.query.db
@@ -42,6 +41,10 @@ function parse(str) {
     // Only set the host if there is no equivalent query param.
     config.host = result.hostname
   }
+  if (!config.port) {
+    // Only set the port if there is no equivalent query param.
+    config.port = result.port
+  }
 
   // If the host is missing it might be a URL-encoded path to a socket.
   var pathname = result.pathname