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: If6fec185f98f3b07b4b10c2fa2c701cf352f10ed

openstack/freezer-api,openstack/freezer-api,openstack/freezer-api,openstack/freezer-api