Updated Travis CI to run composer install for Drupal 8.1.x

.travis.yml

@@ -55,6 +55,10 @@ before_script:
   # Reference rules in build site.
   - ln -s $TESTDIR modules/rules
 
+  # Run composer install for Drupal 8.1. We need an up-to-date composer when
+  # installing Drupal 8.1.
+  - if [ "$DRUPAL_CORE" = "8.1.x" ]; then composer self-update && composer install; fi
+
   # Start a web server on port 8888, run in the background; wait for
   # initialization.
   - nohup php -S localhost:8888 > /dev/null 2>&1 &
@@ -69,6 +73,6 @@ before_script:
 
 script:
   # Run the PHPUnit tests which also include the kernel tests.
-  - ./vendor/phpunit/phpunit/phpunit -c ./core/phpunit.xml.dist ./modules/rules
+  - ./vendor/bin/phpunit -c ./core/phpunit.xml.dist ./modules/rules
   # Check for coding standards violations
   - cd modules/rules && ~/.composer/vendor/bin/phpcs