Correctly test for canonicalized path in the CreateNamedPipe policy engine.

      BUG=334897
TEST=sbox_integration_tests.exe

Review URL: https://codereview.chromium.org/145553007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247511 0039d316-1c4b-4281-b951-d872f2087c98