Fixed build error in AnyPromise.m
Fixed build error in AnyPromise.m

When installing PromiseKit 6 as a static library via CocoaPods.
The problem is described in the following issue - https://github.com/mxcl/PromiseKit/issues/825.
mxcl/PromiseKit,mxcl/PromiseKit,mxcl/PromiseKit