[travis-ci] Optimize composer install having all requirements set

Avoid to execute the requirements resolution algorithm twice

Author: Maks3w

.travis.yml

@@ -28,6 +28,7 @@ notifications:
 before_install:
   - if [[ $EXECUTE_COVERAGE != 'true' ]]; then phpenv config-rm xdebug.ini || return 0 ; fi
   - composer self-update
+  - if [[ $EXECUTE_COVERAGE == 'true' ]]; then composer require --no-update satooshi/php-coveralls:dev-master ; fi
 
 install:
   - travis_retry composer install --no-interaction --ignore-platform-reqs
@@ -38,5 +39,4 @@ script:
   - if [[ $EXECUTE_CS_CHECK == 'true' ]]; then ./vendor/bin/phpcs --standard=PSR2 src test ; fi
 
 after_script:
-  - if [[ $EXECUTE_COVERAGE == 'true' ]]; then composer require satooshi/php-coveralls:dev-master ; fi
   - if [[ $EXECUTE_COVERAGE == 'true' ]]; then ./vendor/bin/coveralls ; fi