Added git installation instruction. Also fixed typos.
Added git installation instruction.
Also fixed typos.

Mirantis/mos-tempest-runner,avlasov-mos-de/mos-tempest-runner,Mirantis/mos-tempest-runner,obutenko/mos-tempest-runner,obutenko/mos-tempest-runner,avlasov-mos-de/mos-tempest-runner