Fixes keys on reference for ClangStaticAnalyzer

Perl 5.20 returns the following warning on all Analizo's commands on terminal:

```keys on reference is experimental at /usr/share/perl5/site_perl/Analizo/Extractor/ClangStaticAnalyzer.pm line 123, <DATA> line 1.```

So I dereferenced the var according to http://www.tutorialspoint.com/perl/perl_references.htm. I'm not a Perl programmer so I'm sorry if this is completly wrong :)