fixed several errors which occured on `vagrant provision`

Error: /Stage[main]/Pear-after/Exec[php::pear::discover-phpunit]/returns: change from notrun to 0 failed: pear channel-discover pear.phpunit.de returned 1 instead of one of [0]
Error: pear install --alldeps phpunit/PHPUnit returned 1 instead of one of [0]
Error: pear install pear.phpunit.de/phploc returned 1 instead of one of [0]