Fix undefined variable warning from Sonar

- 'exceptions' was implicitly defined by the wildcard import
- wildcard imports are dubious style anyway, but Sonar explicitly
  objected to this case since qpid.exceptions is a submodule that
  is automatically imported in the qpid package's __init__ module
  rather than a normal assignment or class or function definition.

Change-Id: I1576ed9f59b500d0228b7b8e87bc58677262eafa
Merge "Fix undefined variable warning from Sonar" into develop