zaqar.conf.sample file can be generated by tox -e genconfig commnad.
The generated zaqar.conf.sample file is supposed to have a [drivers]
section as per zaqar README.rst
However, the [drivers] section is not present in zaqar.conf.sample file
This patch fixes it
Closes-bug: #1501130
Change-Id: Ic1d98680fe1040f68944b529b1c4c4ec2c835cea