Most of the pl/pgsql functions and variables are prefixed plpgsql_, so they don't risk conflicting with other shared libraries loaded.
There are a couple that are not prefixed. Attached patch fixes that. It's mostly a cleanup, but I think it's something we should do since it's only 2 variables and 2 functions.
AFAICT these are clearly meant to be internal. (the plugin variable is accessed through find_rendezvous_variable)
