Add Zend Framework 1 to travis configuration

https://github.com/TechEmpower/FrameworkBenchmarks/pull/874#issuecomment-51728539

.travis.yml

@@ -123,6 +123,7 @@ env:
     - "TESTDIR=PHP/php-yaf"
     - "TESTDIR=PHP/php-yii2"
     - "TESTDIR=PHP/php-zend-framework"
+    - "TESTDIR=PHP/php-zend-framework1"
     - "TESTDIR=PHP/phreeze"
     - "TESTDIR=Python/bottle"
     - "TESTDIR=Python/django"