We need the gcc and other dependencies
installed before we can do any tox related
commands.

Installation of git was never checked in QSG.
I happened to create a baremetal CentOS server
with minimal install and there was no git.
Added steps to install git.

Moved the steps related to git clone and other
kolla configuration after basic installation.
since tox fails for gcc.

In the quickstart guide we are generating
the configuration using tox but tox is not
installed before doing so. Adding steps to
install tox before generating conf.

Change-Id: Ic8a756e66d33963e47607ed60c4c768e0859152d