Bug 18936: (follow-up) Add foreign key and scope enhancement to circ rules

Bug 18936: (follow-up) Add foreign key and scope enhancement to circ rules

The previous patch modifies:
-                categorycode => undef,
-                itemtype     => undef,
-                branchcode   => $branch,
+                branchcode   => undef,

But in that condition $branchcode is not '*' and so we should not set it
to undef

Signed-off-by: Minna Kivinen <minna.kivinen@hamk.fi>
Signed-off-by: Joonas Kylmälä <joonas.kylmala@helsinki.fi>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>