add-apt-repository is provided by another package

add-apt-repository is provided by software-properties-common instead of python-software-properties in Ubuntu 14.04

```bash
eploy@server2:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 14.04.1 LTS
Release:	14.04
Codename:	trusty
deploy@server2:~$ apt-file search add-apt-repository
software-properties-common: /usr/bin/add-apt-repository
software-properties-common: /usr/share/man/man1/add-apt-repository.1.gz
deploy@server2:~$
```