Updated phpunit testing mail settings due to laravel 5.2 changes

@@ -25,7 +25,7 @@
         <env name="SESSION_DRIVER" value="array"/>
         <env name="QUEUE_DRIVER" value="sync"/>
         <env name="DB_CONNECTION" value="mysql_testing"/>
-        <env name="MAIL_PRETEND" value="true"/>
+        <env name="MAIL_DRIVER" value="log"/>
         <env name="AUTH_METHOD" value="standard"/>
         <env name="DISABLE_EXTERNAL_SERVICES" value="false"/>
         <env name="LDAP_VERSION" value="3"/>