bug: searching for method names incorrectly when there's an acronym

[sofisl]

1. gRPC reads proto definitions and generates an object that, for each rpc in the proto definition, defines a method that would call that RPC for
2. so if your proto has rpc SomeFunc(Request) returns (Response), and you pass this proto to gRPC, it will return an object (that we call a stub) that would have stub["someFunc"], note the camelCase
3. When stubs are generated for methods that have an acronym in them, they get generated like such: createOsPolicyAssignment, but the generated code looks for the method name createOSPolicyAssignment

We need to make sure we're looking for the right method name.

See: googleapis/nodejs-os-config#173