travis: drop distribution related change check.

Managed to get the spec building quick enough it does not matter and the
check would need to be more complicated to not miss a variety of cases.

.travis.yml

@@ -6,15 +6,6 @@ matrix:
         - docker
       language: bash
       before_install:
-        - |
-          # Always run on custom branches in main project as diff does not work.
-          if [ "$TRAVIS_BRANCH" == "master" ] || [ "$TRAVIS_PULL_REQUEST" != "false" ] ; then
-            echo "Checking to see if skippable..."
-            if ! git diff --name-only "$TRAVIS_COMMIT_RANGE" | grep -qE '^(\.travis.yml|dist\/.*)$' ; then
-              echo "No distribution related changes, stopping build process."
-              exit
-            fi
-          fi
         - docker build -f dist/ci/Dockerfile -t spec .
       script:
         - docker run -it spec ./dist/ci/spec.sh