Remove Quota Exception Stack Traces from Cinder Logs

Added an if clause to the Cinder API FaultWrapper so that
a warning is printed rather than an error and stack trace
if an exception of type QuotaError is thrown.

Closes-Bug: 1324294
Change-Id: If91db0f443afc212af3893e27dd36f19b15c43bf
Merge "Remove Quota Exception Stack Traces from Cinder Logs"