Some minor stuff

By taking a look over the current SSL pinning feature, I figured than

* `Security.framework` doesn't define `noErr` but rather `errSecSuccess` as `OSStatus` and it's good practice to use the frameworks defined status codes in case they might eventually change in the future.
* `+[NSURLConnectionOperation pinnedPublicKeys]` was using `NSCParameterAssert` instead of `NSParameterAssert` which I think is wrong here because its an objc method implementation.