Update package name for netcat on Debian

Summary:
The 'nc' package doesn't exist anymore. Two netcat versions are
now available, the OpenBSD and the legacy ones.

This change picks the netcat-openbsd package.

Fixes T1567.

Test Plan: salt eglide state.sls roles/core/userland-software

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1567

Differential Revision: https://devcentral.nasqueron.org/D2143