Added script to set up extension

As per https://github.com/travis-ci/travis-ci/issues/2523 it appears that the
php.ini on hhvm is in a different place. Created a script to write the
extensions to the right php.ini based on the environment.

tests/travis.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+VERSION=`phpenv version-name`
+
+if [ "$VERSION" -eq "hhvm" ]
+then
+    PHPINI=/etc/hhvm/php.ini
+else
+    PHPINI="~/.phpenv/versions/$VERSION/etc/php.ini"
+fi
+
+echo "extension = memcache.so"  >> $PHPINI
+echo "extension = memcached.so" >> $PHPINI
+echo "extension = redis.so"     >> $PHPINI