Update travis setup.

Signed-off-by: crynobone <crynobone@gmail.com>

.travis.yml

@@ -7,16 +7,26 @@ php:
   - 7.0
   - hhvm
 
+env:
+  global:
+    - DEFAULT=1
+
 before_script:
   - travis_retry composer self-update
-  - if [[ "$TRAVIS_PHP_VERSION" == *5.6* ]]; then travis_retry composer require "satooshi/php-coveralls:~0.6.1" "symfony/yaml=~2.0" --prefer-source --no-interaction --dev; else travis_retry composer install --prefer-source --no-interaction; fi
+  - if [[ $DEFAULT = '1' ]]; then travis_retry composer install --prefer-source --no-interaction; fi
+  - if [[ $COVERALLS == '1' ]]; then travis_retry composer require "satooshi/php-coveralls=~0.6" "symfony/yaml=~2.0" --prefer-source --no-interaction --dev; fi
 
-script: if [[ "$TRAVIS_PHP_VERSION" == *5.6* ]]; then phpunit -c phpunit.xml --coverage-clover build/logs/clover.xml; else phpunit -c phpunit.xml; fi
+script:
+  - if [[ $COVERALLS == '1' ]]; then phpunit -c phpunit.xml --coverage-clover build/logs/clover.xml; fi
+  - if [[ $DEFAULT = '1' ]]; then phpunit -c phpunit.xml; fi
 
 after_script:
-  - if [[ "$TRAVIS_PHP_VERSION" == *5.6* ]]; then php vendor/bin/coveralls -v; fi
+  - if [[ $COVERALLS == '1' ]]; then php vendor/bin/coveralls -v; fi
 
 matrix:
+  include:
+    - php: 5.4
+      env: COVERALLS=1 DEFAULT=0
   allow_failures:
     - php: 7.0
     - php: hhvm