[WWcvs] pg: HEAD backport: Defined some variables that were causing warning

[Sam H. v. a. <act...@de...>]

Log Message:
-----------
HEAD backport: Defined some variables that were causing warning
messages. (gage)

Tags:
----
rel-2-1-patches

Modified Files:
--------------
    pg/lib:
        AlgParser.pm

Revision Data
-------------
Index: AlgParser.pm
===================================================================
RCS file: /webwork/cvs/system/pg/lib/AlgParser.pm,v
retrieving revision 1.6
retrieving revision 1.6.2.1
diff -Llib/AlgParser.pm -Llib/AlgParser.pm -u -r1.6 -r1.6.2.1
--- lib/AlgParser.pm
+++ lib/AlgParser.pm
@@ -536,6 +536,7 @@
     return ($args[0] . $p1 . $args[1]->tolatex() . $p2);
   };
   /binop2/ && do {
+    my ($p1, $p2, $p3, $p4)=('','','','');
     my ($lop,$rop) = ($args[1]->tolatex,$args[2]->tolatex);
     if ($args[0] eq '/'){
       return('\frac{'.$lop.'}{'.$rop.'}');