Bug 5824: Creating a circ rule for a specific library causes anomalies

Bug 5824: Creating a circ rule for a specific library causes anomalies

The variable name for the current branch being edited was the same as the variable used in
cat-search.inc, which passed along the circ-rule library to circulation.pl, and then overriding
the set library from there.

This patch renames the template variable 'current_branch', so that it does not populate the 'branch'
param in cat-search.inc

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>