Remove @nosideeffects from create-react-class

[tupton]

Fixes the remaining issue with @nosideeffects and the create-react-class addon, as mentioned in #7551 (context.)

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[gaearon]

Please send this against 15.6-dev instead. Thanks!

[gaearon]

Closing in favor of #9933 (against the correct branch), thanks for raising awareness though.

[gaearon]

This should be fixed in create-react-class@15.6.0-rc.0. Please verify, it will become 15.6.0 tomorrow.