[pitivi] .gitlab-ci.yml: Disable TLS

[Alexandru Băluț <alexbalut src gnome org>]

commit 288363a42d6129a28628b27ba72d7b41bf3824cc
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Jan 20 00:38:31 2020 +0100

    .gitlab-ci.yml: Disable TLS
    
    As per https://about.gitlab.com/releases/2019/07/31/docker-in-docker-with-docker-19-dot-03/
    this fixes the docker error:
    
        docker: Cannot connect to the Docker daemon at tcp://docker:2375.

 .gitlab-ci.yml | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2218e8f4..39596cf0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -57,6 +57,9 @@ deploy:
 # and it is not possible to use a privileged `docker build`.
 .build_emplate: &build_docker_image
     image: docker:latest
+    variables:
+        DOCKER_DRIVER: overlay2
+        DOCKER_TLS_CERTDIR: ""
     services:
         - docker:19.03.0-dind
     script: