python - be: Remove call argument overrides.

Log Message:
-----------
Remove call argument overrides.

This is useful for state keeping calls that can take later arguments. Primarily,
non-SRF generators(plpy functions), and for optimizing repeat calls to Postgres
functions. However, the code expects a list for the already created arguments,
which is no longer the norm. So, defer to removing the code for now. Also, using
this feature requires that the user explicitly create the call object, which is
more or less a nuisance.

Modified Files:
--------------
    be/src:
        call.c (r1.10 -> r1.11)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/call.c.diff?r1=1.10&r2=1.11)