Fix method redefinition warnings

[jonathanhefner]

Seahorse::Client::Base.define_operation_methods generically defines methods for a client API. Later, generated client class code explicitly defines those methods. To prevent method redefinition warnings, make define_operation_methods define the generic methods in an anonymous module, which is then included into the client class.

Also, fix a conflict between an attr_accessor and an explicitly defined reader method.

Fixes #2070.

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[jonathanhefner]

Sidenote: I'm not sure how necessary define_operation_methods is. Tests in aws-sdk-core fail without it, but it seems like it is completely obviated by the generated client code. If it could be removed, that would marginally reduce memory consumption (from all the methods it defines, that are subsequently discarded). Perhaps someone with more insight can comment.

[mullermp]

Thanks for opening this. Sorry for the delay (was out on vacation). When I first looked at this, I was thinking similarly. @cjyclaire has been on the team long enough to know the answer to that.

[cjyclaire]

Thanks for the contribution, and appreciate the thoughts there!

The reason for #set_api is that, there are many plugins/middleware stack registered per client are still using the @api definition to achieve functionalities, we are definitely thinking about removing this pattern and doing all static generation in the long run :) , but for the short term future, it's still needed.

Taking a look at the diff now

[cjyclaire]

Looks great, would appreciate it if a changelog entry can be added here, thus we can track this in our next release :)

[jonathanhefner]

@cjyclaire Done!