Update LICENSE to 2017

What does this MR do?

Make the LICENSE realize that it is 2017 already.

Are there points the reviewer needs to double check?

The calendar.

Why was this MR needed?

2017 has started.

Screenshots

https://www.wolframalpha.com/input/?i=today

mentioned in merge request gitlab-development-kit!251 (merged)

mentioned in merge request gitlab-shell!121

mentioned in merge request gitlab-workhorse!124 (merged)

mentioned in merge request gitlab-ci-yml!42 (merged)

mentioned in merge request gitlab-qa!56 (merged)

mentioned in merge request gitlab-monitor!36 (merged)

mentioned in merge request gitlab-pages!12 (merged)

mentioned in merge request cookbook-omnibus-gitlab!44 (merged)

mentioned in merge request gitlab-design!5 (merged)

mentioned in merge request gitlab-omnibus-builder!28 (merged)

changed milestone to %9.0

assigned to @rymai

merged

mentioned in commit tczzjin/gitlab-ce@75092d96