Ignore dial error in dbtest after stopping server. (globalsign#122)

* Ignore dial error when server is stopped. related to globalsign#117

* Print dbtest server starting error before panic.

As seen in globalsign#117, dbtest start() throws a panic when it can't start mongo.
This panic is picked up by a panichandler obscuring the actual problem.
This PR simply prints the error start() encounters to stderr, before throwing the panic.

dbtest/dbserver.go

@@ -69,6 +69,8 @@ func (dbs *DBServer) start() {
 	dbs.server.Stderr = &dbs.output
 	err = dbs.server.Start()
 	if err != nil {
+		// print error to facilitate troubleshooting as the panic will be caught in a panic handler
+		fmt.Fprintf(os.Stderr, "mongod failed to start: %v\n",err)
 		panic(err)
 	}
 	dbs.tomb.Go(dbs.monitor)

dbtest/dbserver_test.go

@@ -77,9 +77,7 @@ func (s *S) TestStop(c *C) {
 	server.Stop()
 
 	// Server should not be running anymore.
-	session, err = mgo.DialWithTimeout(addr, 500*time.Millisecond)
-	c.Assert(err, IsNil)
-
+	session, _ = mgo.DialWithTimeout(addr, 500*time.Millisecond)
 	if session != nil {
 		session.Close()
 		c.Fatalf("Stop did not stop the server")