Reek does not handle relative paths from config file

[dansdantas]

As stated on #1243 , using reek at child level for configurations on ancestors directories does not handle a relative path.

Eg: .reek

"config/":
  IrresponsibleModule:
    enabled: false

reek config/application.rb

 example (master) ✗ reek config/application.rb
 Inspecting 1 file(s):
 .

Child directory - reek application.rb

 config (master) ✗ reek application.rb
 Inspecting 1 file(s):
 S

 application.rb -- 1 warning:
[10]:IrresponsibleModule: Example::Application has no descriptive comment [https://github.com/troessner/reek/blob/master/docs/Irresponsible-Module.md]