Update CI tools to exclude old PHP versions

.gitlab-ci.yml

@@ -8,16 +8,6 @@ cache:
 services:
     - redis:latest
 
-test:5.6:
-    before_script:
-      - bash build/docker_install.sh > /dev/null
-      - curl -sS https://getcomposer.org/installer | php
-      - php composer.phar update
-      - php composer.phar install
-    image: php:5.6
-    script:
-      - vendor/bin/phpunit --coverage-text --colors=never
-
 test:7:
     before_script:
       - bash build/docker_install.sh > /dev/null

.travis.yml

@@ -4,7 +4,6 @@ install:
   - composer install
 
 php:
-  - 5.6
   - 7
   - hhvm
   - nightly