Add compatibility with Debian 9

[jnogol]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Checked that your issue isn't already filled: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aidealista
  • Checked that there is not already provided the described functionality

Description

Add compatibility with Debian 9. Our role needs libcap2-bin package to work, and it comes along with Debian 8 but not with Debian 9. Installing it will solve the problem.