Handle empty build dir correctly

debug.go

@@ -198,8 +198,10 @@ func (cmd *DebugCmd) Run(g *Globals) (err error) {
 	// Copy all test files to the remote machine
 	for _, f := range ka.TestFiles {
 		if f.Local[0] != '/' {
+			if res.BuildDir != "" {
 				f.Local = buildDir + "/" + f.Local
 			}
+		}
 		err = q.CopyFile(f.User, f.Local, f.Remote)
 		if err != nil {
 			log.Print("error copy err:", err, f.Local, f.Remote)