Skip case for fixing incorrect exception assertion

HTTP status code 413 should not used for some exception
response based on RFC2616.

Related nova commit: I2bb8a60ef254afbfed514cfeebe75355d0de4475
Related-Bug: #1298131

Change-Id: If376eda0a7929ba2baa4ac4acbb457883bcfc96d
Merge "Skip case for fixing incorrect exception assertion"