Fixed upload on Arduino Leonardo (and derivatives) with JSSC on Mac.

See arduino#1633

Author: cmaglie

app/src/cc/arduino/packages/uploaders/SerialUploader.java

@@ -89,9 +89,7 @@ public boolean uploadUsingPreferences(File sourcePath, String buildPath, String
           // otherwise assert DTR, which would cancel the WDT reset if
           // it happened within 250 ms. So we wait until the reset should
           // have already occured before we start scanning.
-          if (!Base.isMacOS())
-            Thread.sleep(300);
-
+          Thread.sleep(300);
           uploadPort = waitForUploadPort(uploadPort, before);
         } else {
           Thread.sleep(400);