fix composer conditional for simpler build

Author: photodude

.travis.yml

@@ -46,7 +46,7 @@ before_install:
 install:
   #- composer validate
   - composer config --unset platform.php
-  - if [ -z "$dependencies" ]; then composer install --prefer-dist; fi;
+  - if [ "$dependencies" = "current" ]; then composer install --prefer-dist; fi;
   - if [ "$dependencies" = "lowest" ]; then composer update --prefer-lowest --prefer-dist -n; fi;
   - if [ "$dependencies" = "highest" ]; then composer update --prefer-dist -n; fi;
   - composer show