Merge pull request #385 from rightscale/cornsilk_14_8_acu162901_rightlink_rc3_fixes

Cornsilk 14 8 acu162901 rightlink rc3 fixes
Merge pull request #380 from rightscale/ivory_14_08_acu159972_create_empty_sources_list

Make apt conf generator to create empty /etc/apt/sources.list
acu162818 - do not use 'w' option on instance state file saving.
acu162818 - get Instance state from Agent and not state file
Merge branch 'ivory_14_08_acu162818_fix_concurrent_instance_state_access'

* ivory_14_08_acu162818_fix_concurrent_instance_state_access:
  acu162818 - get Instance state from Agent and not state file
  acu162818 - do not use 'w' option on instance state file saving.