BaseTools: Add the support for python 2

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1875

python3 change the module name of Queue to queue.
python3 add a new log handler of QueueHandler.

This patch is to make Multiple process AutoGen
feature work for python2

Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Bob Feng <bob.c.feng@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/Python/AutoGen/AutoGenWorker.py

@@ -16,7 +16,10 @@ import os
 from Common.MultipleWorkspace import MultipleWorkspace as mws
 from AutoGen.AutoGen import AutoGen
 from Workspace.WorkspaceDatabase import BuildDB
-from queue import Empty
+try:
+    from queue import Empty
+except:
+    from Queue import Empty
 import traceback
 import sys
 from AutoGen.DataPipe import MemoryDataPipe