LEGACY.CHIDIST and LEGACY.CHIINV: remove LEGACY prefix

Hi,

We have prefixed LEGACY.CHIDIST and LEGACY.CHIINV, I don't think that is
appropriate. We also don't have superior functions replacing them.
I propose to remove the prefix from those two functions.

  Eike

-- 
Automatic string conversions considered dangerous. They are the GOTO statements
of spreadsheets.  --Robert Weir on the OpenDocument formula subcommittee's list.