Tumblr logout bug (with fix)

[smkiewel]

Tumblr logout is not working. This is because [SHK logoutOfService:@"ServiceClassName"]; calls [ServiceClassName authorizationFormFields] as a class method, but the Tumblr implementation only provides the instance method. This instance method needs to be changed to a class method, i.e. line 111 needs the - changed to a +.

[javierfigueroa]

Thanks for finding this!