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: Iccbd680731592abab4980a51aa97c60d6ef95005

openstack/heat,openstack/heat,noironetworks/heat,noironetworks/heat