Bupt branch merge
- Detect internet environment, change ubuntu source if it is in China
- ssh.py is downloaded from bupt server, as the repository on github is blocked in China.
- SPGW is switched to master branch, revision "head" (using kernel 4.7)
- OAISIM info is written into database when HSS installed.
- HSS is switched to master branch
- Some other config file tweaks.