pygpt: Fix execution failure in show and prioritize command.

There was one typo in the property name (forget to change in last
refactoring): type_guid should be TypeGUID.

BUG=chromium:834237
TEST=make test

Change-Id: I1ce10b4a019bc6e7df79073ed2b97cea1caa6d83
Reviewed-on: https://chromium-review.googlesource.com/1042326
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Pi-Hsun Shih <pihsun@chromium.org>
diff --git a/py/utils/pygpt.py b/py/utils/pygpt.py
index 6a8a0bd..4474061 100755
--- a/py/utils/pygpt.py
+++ b/py/utils/pygpt.py
@@ -475,7 +475,7 @@
 
     def IsChromeOSKernel(self):
       """Returns if the partition is a Chrome OS kernel partition."""
-      return self.type_guid == GPT.TYPE_GUID_CHROMEOS_KERNEL
+      return self.TypeGUID == GPT.TYPE_GUID_CHROMEOS_KERNEL
 
     @property
     def blocks(self):