Review #32
This code will go into both server 1.32 branch and the viewer branch.
As proposed in DEV-41949, I've changed setWhitelist(const LLSD &whitelist) to clear the whitelist if the WHITELIST_KEY is not present in the passed-in 'whitelist'. I've also made sure that asLLSD() ensures that the WHITELIST_KEY is erased in the given LLSD.