Make React 0.14 compatible with prop-types

[gaearon]

Never thought I'd go back to 0.14 but here we are: reduxjs/react-redux#669.

It's reasonable for standalone prop-types package to support both 0.14 and 15 to ease the migration effort for library authors. So let's release React 0.14.9 that “understands” standalone prop-types by passing the secret.

(Also I hope this doesn't get me fired?)

[bvaughn]

Disclaimer: I don't know 0.14 internals at all

But this change looks okay to me.

We're passing null for propFullName in few places where the value was previously undefined but looking at the source, that shouldn't make a difference.

[gaearon]

Verified it works by creating a new project using react-redux@4. No longer printing a ton of messages. Tests pass.