Removed system() call

[nafigator]

In some systems php is running under strict security ini-settings. For example: disable_functions="chdir,dl,ini_get_all,system,shell_exec,popen,proc_open,passthru,pcntl_execchdir,dl,ini_get_all,system,shell_exec". To be able run PHPLinter on such systems system() call should be removed.