Append suffixes correctly for phpcpd

[omarlopesino]

Since phpcpd has released the 6.0 version the --names have been removed in favour of the new argument --suffix. This change has been adapted at PHPqa project but it needs a correction.

CUrrently, the --suffix arguments is added by joining all the suffixes by commas. Example:

--suffix="*.php,*.theme,*.module"

But that syntax is not correct. This is the documentation of the suffix command from PHPcpd:

  --suffix <suffix> Include files with names ending in <suffix> in the analysis
                    (default: .php; can be given multiple times)

The suffix parameter only accepts one suffix, and if it is needed to add more suffixes, the --suffix parameter must be repeated. So, the example I shown below should be corrected to this:

--suffix="*.php,*.theme,*.module" --suffix="*.module" --suffix="*.theme"

This pull request fixes the usage of suffix to be added by repeating suffix arguments and not joining the suffixes by commas. Please review, thanks!

[omarlopesino]

The PHP 5.6 tests are failing but it does not look like a fail related to the changes done in the PR:

[omarlopesino]

I've done the requested changes. Please review, thanks!