docstring fix

The docstring of class Extended_availability_zone was totally same as
Extended_server_attributes. This patch improves this docstring.

Change-Id: Ifd59d8dd149975c7f2653a0e0effadfc88d119d4
Fix string formatting of exception.NoUniqueMatch message

There is no implicit logger string formatting happening, so
we need to do this on our own.

Change-Id: I13dfb804d55b5ede2987e355f8a932f237b56c56
Sync unhandled exception logging change from Oslo

Copying changes from 1 Oslo commit: Ibf00173a07510b2ec0c81a29624004f17810a4e4
This is related to the bug fix for adding error type to unhandled
exception log message.

Change-Id: Ie8af57a148753121f79136af928feb0edaea228b
Closes-Bug: #1265561
Merge "Sync unhandled exception logging change from Oslo"
Merge "Fix string formatting of exception.NoUniqueMatch message"
Merge "docstring fix"