Fix long-standing typos in Policy_sh.SH

Fix long-standing typos in Policy_sh.SH

This patch fixes several long-standing typos and naming confusions in
Policy_sh.SH, standardizing on the variable names used in config.sh.
This will change the behavior of Policy.sh if you happen to have been
accidentally relying on the Policy.sh incorrect behavior.  I'd appreciate
feedback from anyone using Policy.sh to be sure nothing is broken by
this change.  Thanks to Stoned Elipot for pointing this out.

Signed-off-by: H.Merijn Brand <h.m.brand@xs4all.nl>