BaseTools: Remove equality operator with None

replace "== None" with "is None" and "!= None" with "is not None"

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>

BaseTools/Source/Python/UPT/Core/PackageFile.py

@@ -56,7 +56,7 @@ class PackageFile:
                             ExtraData="%s (%s)" % (FileName, str(Xstr)))
 
         BadFile = self._ZipFile.testzip()
-        if BadFile != None:
+        if BadFile is not None:
             Logger.Error("PackagingTool", FILE_CHECKSUM_FAILURE, 
                             ExtraData="[%s] in %s" % (BadFile, FileName))