pbr 1.0.1 released in 2015-05-19 requires the newer
hacking module >=0.10.0,<0.11 than the versions
specified in the test-requirement.txt file,
which causes failure in gate-python-cinderclient-pep8.

This patch bumps the pbr version in test-requirement.txt
to make it consistent with requirements repository,
and adds some fixups to avoid some new hacking rules.

Change-Id: I7de6e04e30a475ec1c26224461faf0c708178a40
Closes-Bug: #1460774

Parser.listing method return empty list if env doesn't have resources,
so assertTableStruct works wrong, doesn't check field names in the
output table.

This change add new assert(assertTableHeaders) to check resource
attributes.

Change-Id: Ieca67b5cc2202467527c5a2dfbd7b2f2b4d5ad8d
Closes-Bug: #1458932

Findall method in cinderclient/base.py isn't very efficient: it loads
the entire list then filters on the Python side. When calling "cinder
show 'volName'" on a tenant holding a lot of volumes (> 1000) the run
time is too long.

On my env show command with 10000 volumes takes ~2 min, after apply
this patch few seconds.

Closes-Bug: #1449444
Change-Id: I23070d94d5bb100b2dd8677f67d7c8b1e7d34e52

With the recent update to tox 2.0.x, environment variables such as
OS_AUTH_URL are not passed by default, resulting in tests errors
mentionning Keystone authentication failures.

This patch reads credentials from the 'functional_creds.conf' config
file, like it is done in novaclient (and soon in glanceclient and
neutronclient).

Reading credentials the old way (the environment) is still possible.

Change-Id: I2ec1df481aba7a3866fc8dbc912311de02c22d11
Related-Bug: #1455102