Avoid to set refs on stateless components

[farwayer]

fix #865 #750

[msftclas]

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[msftclas]

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[chirag04]

Maybe it's better explicitly ask for withRef option like how redux connect does

[farwayer]

Ask for what? ref used internally only to make codePushStatusDidChange and codePushDownloadDidProgress functions work. With stateless components it is senselessly.

[chirag04]

Set the ref only if withRef option is provided and check if ref exists before using it in any function

[max-mironov]

Hi @farwayer , thank you so much for contribution, your PR looks good for me, I've also tested it one more time and haven't found any issues with this.

@chirag04 - could you please explain a little bit more your point - what are the benefits here with adding withRef option in such particular case?

[max-mironov]

Guys - I believe we can merge this changes to Master and we can always enhance this in future if needed. Please feel free to voice your concerns or suggestions if any.