[DRE-maint] Bug#956504: Switch dependency from ruby-parser to ruby-ruby-parser

[Pirate Praveen]

Package: obs-api
Version: 2.9.4-2
Severity: important
Control: tags -1 patch

ruby_parser gem is now renamed to ruby-ruby-parser package to allow 
packaging parser gem as ruby-parser.

I have pushed a commit to master, a new upload of abs-api will allow us 
to upload a new ruby-parser package.