Fix HHVM support for CLI

HHVM 3.0.1 doesn't like the -q flag used in the PHP command-line. Moving
the flag into findPhpBinary() in CliPhp adds compatibility with HHVM.
Previously mentioned in piwik/piwik/#5263
Add the missing -q flag

Forgot a ``-q`` flag from the rest of the findPhpBinary() function. This behaves like the current version of Piwik, adding the ``-q`` flag to the command-line in case the Cli is PHP
Merge pull request #5818 from Diftraku/hhvm_comp

Fix HHVM support for CLI