Don't quote {posargs} in tox.ini
Don't quote {posargs} in tox.ini

Quotes around {posargs} cause the entire string to be combined into one
arg that gets passed to stestr. This prevents passing multiple args
(e.g. '--concurrency=16 some-regex')

Change-Id: I7f47ce264dffd4de203d59def1d4c9e2949a9fb8

openstack/stackalytics,stackforge/stackalytics,0xf2/stackalytics,0xf2/stackalytics,0xf2/stackalytics,openstack/stackalytics,stackforge/stackalytics,openstack/stackalytics,openstack/stackalytics,0xf2/stackalytics,stackforge/stackalytics