rbutil: Fix Xduoo bootloader installation.

- Don't try to unzip the bootloader file if we're actually looking for a
  zip file.
- Fix wrong bootloader file name for X3.
- There's no QThread::terminated() signal, don't connect it.

Change-Id: Iebfcc61d644c8443b60d9b37f4932d7b46098465

rbutil/rbutilqt/base/bootloaderinstallbspatch.cpp

@@ -110,7 +110,6 @@ void BootloaderInstallBSPatch::installStage2(void)
     m_tempfile.close();
     m_patchedFile.close();
     connect(m_thread, SIGNAL(finished()), this, SLOT(installStage3()));
-    connect(m_thread, SIGNAL(terminated()), this, SLOT(installStage3()));
     m_thread->start();
 }