[Serusers] revert uri to its early state, but no the original

[Juha Heinanen]

Richard writes:

 > I wonder if there is any function to save uri and retrieve it later.
 > Something like, save_uri(2) to save it to storage 2 and pop_uri(2) to get it
 > back.

i don't think that there is yet such a function, but it could easily
implemented using the new avp functions.

-- juha