[autohelp] display information on import error
[autohelp] display information on import error

When a module import fails the wrapper script doesn't display its
path/name, so it is complicated to debug. this patch displays the module
name before re-raising the exception.

Change-Id: Ie9d691a41b0c178b856f19605a8c6434d3ce2c88

openstack/openstack-doc-tools,openstack/openstack-doc-tools