Fix .travis.yml for PHP7 and try to fix a DB test
diff --git a/.travis.yml b/.travis.yml
index 26b194f..258ad76 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,7 +39,7 @@
     - php: hhvm
       env: DB=pdo/pgsql
     - php: 7
-      env: mysql
+      env: DB=mysql
     - php: 5.2
       env: DB=sqlite
     - php: 5.2