Merge pull request #379 from rightscale/ivory_14_07_acu160049_prepare_rc2

acu160049 - bump right_link version and update release docs for RC2
acu159972 make apt conf generator to create empty /etc/apt/sources.list
acu159972 do not create sources.list.ORIG if sources.list is missing or empty
Merge pull request #381 from rightscale/ivory_14_08_acu159972_create_empty_sources_list

Make apt conf generator to create empty /etc/apt/sources.list