generate_sample.sh does not generate sample configuration for modules using "_" builtin.

[Ann Taraday]

If we use generate_sample.sh for modules that contains "_" builtin and has configuration declaration, it won't gererate samlpe configuration for such module.
generate_sample.sh calls extract_opts.py, so the problem is in the extract_opts.py.
For example,

akamyshnikova@akamyshnikova:/opt/stack/cinder$ python tools/conf/extract_opts.py cinder/backup/manager.py
####################
# cinder.conf sample #
####################

[DEFAULT]

# Total option count: 0
akamyshnikova@akamyshnikova:/opt/stack/cinder$

If we use debug for this command we see that

 /opt/stack/cinder/tools/conf/extract_opts.py(81)_print_module()
-> mod_obj = importutils.import_module(mod_str)
(Pdb) n
NameError: "name '_' is not defined"

So, if we add to extract_opts.py

import __builtin__
setattr(__builtin__, '_', lambda x: x)

everything works correctly:

akamyshnikova@akamyshnikova:/opt/stack/cinder$ python tools/conf/extract_opts.py cinder/backup/manager.py
####################
# cinder.conf sample #
####################

[DEFAULT]

#
# Options defined in cinder.backup.manager
#

# Service to use for backups. (string value)
#backup_service=cinder.backup.services.swift

# Total option count: 1

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/30235
Committed: http://github.com/openstack/cinder/commit/9cdccf36c6d8a07cfdc3ee0e974736951317005b
Submitter: Jenkins
Branch: master

commit 9cdccf36c6d8a07cfdc3ee0e974736951317005b
Author: Ann Kamyshnikova <email address hidden>
Date: Thu May 23 13:33:30 2013 +0400

    Add "_" builtin method for config generation

    extract_opts.py fails to generate config without this

    bug 1183731

    Change-Id: Icf3b45d5d7262607336f5d5e7a0a14b0dee9741d