Travis CI: Fix the $GROUP env. var. matrix

Author: dumbbell

.travis.yml

@@ -15,7 +15,8 @@ otp_release:
   - "18.0"
 env:
   matrix:
-  - GROUP=1 GROUP=2
+  - GROUP=1
+  - GROUP=2
 
 # The checkout made by Travis is a "detached HEAD" and branches
 # information is missing. Our Erlang.mk's git_rmq fetch method relies on
@@ -25,7 +26,6 @@ env:
 # created, pointing to the detached HEAD.
 before_script:
   - |
-    if test "${GROUP}" != "1"; then exit 0; fi
     git checkout -B "${TRAVIS_TAG:-${TRAVIS_BRANCH}}"
     git remote add upstream https://github.com/$TRAVIS_REPO_SLUG.git
     git fetch upstream stable:stable || :