Added repos for new fabric and ubuntu-cloud-archive in sources.list of lb

Fabric version in ubuntu repos are older version which lacks some required features.
So added chris-lea ppa for newer version of fabric and added ubuntu-cloud-archive for
python-paramiko version which is required for new fabric.
Merge pull request #11 from hkumarmk/add_apt_sources

Added repos for new fabric and ubuntu-cloud-archive in sources.list of l...