SAR deregistration changes, untested
Minor fix
Delete IMS subscriptions on deregisters regardless of HSS result code
Fix bugs caught by UT
Mark ups after review
Updates to cpp-common
Merge pull request #28 from Metaswitch/submodule_update

[No reviewer] Updates to cpp-common
Give homestead ownership of log directory when it already exists
Merge pull request #29 from Metaswitch/log_directory_permissions

Give homestead ownership of log directory when it already exists
Use an enum for the Server-Assignment-Types and change default Server-Assignment-Type when no IMPI is specified
Use the enum type on the Cx interface
Change Server Assignment Types enum name and structure
Merge pull request #25 from Metaswitch/sto635

sto635 - SAR deregistration support