travis: always run the "Build & test" stage first

Now that the other stages are explicitly listed in the "stages"
section, we should include "Built & test" there to make sure
it's run first.

.travis.yml

@@ -11,6 +11,9 @@ env:
         - REPO_ROOT="$TRAVIS_BUILD_DIR"
 
 stages:
+    - name: Build & test
+      if: type != cron
+
     - name: Fuzzit-Fuzzing
       if: type = cron