Move docker:dind service to build steps which require it

.gitlab-ci.yml

@@ -13,13 +13,13 @@ stages:
  - check
  - build
 
-services:
- - docker:dind
 
 dockerimage_builder:
   stage: prepare
   before_script:
     - apk add --no-cache make
+  services:
+   - docker:dind
   script:
     - docker pull $DOCKER_IMAGE_BUILDER || true
     - docker login -u gitlab-ci-token -p $CI_BUILD_TOKEN $CI_REGISTRY
@@ -37,6 +37,8 @@ dockerimage_security_scanner:
   stage: prepare
   before_script:
     - apk add --no-cache make
+  services:
+   - docker:dind
   script:
     - docker pull $DOCKER_IMAGE_SECURITY_SCANNER || true
     - docker login -u gitlab-ci-token -p $CI_BUILD_TOKEN $CI_REGISTRY
@@ -70,6 +72,8 @@ security_scanner:
   stage: build
   before_script:
     - apk add --no-cache make
+  services:
+   - docker:dind
   script:
    - make images/debian-stretch.squashfs
   artifacts: