Use current pillarenv if nothing specified with argument
Use current pillarenv if nothing specified with argument

... instead of overwriting it with 'None' and getting merged pillar
environments.
This is actual at least for pillar.items call that should return actual
pillar data for the minion, but currently it returns merged data from
all available environments.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt