It wont happen for a number of reasons.

1. not enought money in it for Haye.
2. Chisora has shown a strong chin , so it is a very ricky fight for Haye, with no rewards.
3. Chisora isnt a big name so i dont think he will get his lisence back.

Haye is rich and a big name Chisora is not , that why CHisora is calling Haye out , because he knows Haye is the MONEY maker.