Fix patch_unittest.py
Fix patch_unittest.py

BUG=None
TEST=Unit test.

Change-Id: I75b6dc53e57567aaf8a4b06f46c933896287a3df
Reviewed-on: http://gerrit.chromium.org/gerrit/4532
Reviewed-by: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>
Tested-by: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>

coreos/chromite,bpsinc-native/src_third_party_chromite,coreos/chromite,zhang0137/chromite,chadversary/chromiumos.chromite,zhang0137/chromite,zhang0137/chromite,chadversary/chromiumos.chromite,coreos/chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite