Fixes #4673 In case the PHP binary used is php-cgi instead of PHP cli…

…, add -q flag to hide http headers from output.

core/CliMulti.php

@@ -94,7 +94,7 @@ private function buildCommand($query, $outputFile)
     {
         $bin = $this->findPhpBinary();
 
-        return sprintf('%s %s/console climulti:request %s > %s 2>&1 &',
+        return sprintf('%s -q %s/console climulti:request %s > %s 2>&1 &',
                        $bin, PIWIK_INCLUDE_PATH, escapeshellarg($query), $outputFile);
     }