moving hostname logic to the common role
removing hostname, adding common
using var for global bashrc update
updating COMMON_HOSTNAME
updating case for common_hostname
changing case for hostname
adding deploy_common
moving prompt default to the gh_users role
empty list default for gh_users
updating deploy_common play
fixing comment
adding default bashrc files for gh_users role
capitalization
Merge pull request #433 from edx/jarv/add-hostname-to-common

Jarv/add hostname to common