Suggest that we remove TSHttpTxnRedirectRequest

[Susan Hinrichs]

Noticed this while tracking down redirect asserts.  It is only used in 
experimental.h.  Not sure what the function is trying to achieve.

Any distress about cleaning it out of InkAPI.cc?
TSReturnCode  TSHttpTxnRedirectRequest(TSHttpTxn txnp, TSMBuffer bufp, 
TSMLoc url_loc)