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