There is plan to remove all oslo incubator code from the
clients. This removes the usage of deprecated
openstack.common.apiclient.exceptions in glance client
plugin.
The available glance HTTPNotFound exception is not usable
for validations(no message) and there is no UniqueMatch
exception.
This adds a new custom client_exception module with two
exceptions to ensure that the error messages remain the
same as before.
Change-Id: I5b32eef047a1fe38382f649532c8bb8a910315e5
e1237f48ef