Remove TLSv1 support from defaults

We've kept TLSv1 in the list of defaults for a long while. The reason for this was that old Java IDE's would not be able to function with GitLab. However, the time has moved on and so should we.

I propose we remove TLSv1 from the list of default protocols for GitLab 10.

/cc @gitlab-build-team @joshlambert