Commit 1f89beb6098f4f6a8d8c2912392b273bc068b2e3 introduced the behaviour
that a stacktrace is printed if an exception is encountered.
This helped make the client more supportable:
$ glance --debug image-list
.
.
.
File "glanceclient/common/http.py", line 337, in get_http_client
xxx
NameError: global name 'xxx' is not defined
global name 'xxx' is not defined
The behaviour was lost at some point. This patch re-enables it.
Change-Id: I25fc8624797909d606590747f54b9cf649ade079
Closes-bug: 1563830