[WWcvs] webwork-modperl: Fixed a bug where a set named "0" would not be sticky

[jj v. a. <we...@ma...>]

Log Message:
-----------
Fixed a bug where a set named "0" would not be sticky in the Target Set
list (because it looked kind of like an empty/undefined name).

Modified Files:
--------------
    webwork-modperl/lib/WeBWorK/ContentGenerator/Instructor:
        SetMaker.pm

Revision Data
-------------
Index: SetMaker.pm
===================================================================
RCS file: /webwork/cvs/system/webwork-modperl/lib/WeBWorK/ContentGenerator/Instructor/SetMaker.pm,v
retrieving revision 1.54
retrieving revision 1.55
diff -Llib/WeBWorK/ContentGenerator/Instructor/SetMaker.pm -Llib/WeBWorK/ContentGenerator/Instructor/SetMaker.pm -u -r1.54 -r1.55
--- lib/WeBWorK/ContentGenerator/Instructor/SetMaker.pm
+++ lib/WeBWorK/ContentGenerator/Instructor/SetMaker.pm
@@ -725,7 +725,8 @@
 
 	if($have_local_sets ==0) {
 		$list_of_local_sets = [NO_LOCAL_SET_STRING];
-	} elsif (not $set_selected or $set_selected eq SELECT_SET_STRING) {
+	} elsif (not defined($set_selected) or $set_selected eq ""
+	  or $set_selected eq SELECT_SET_STRING) {
 		unshift @{$list_of_local_sets}, SELECT_SET_STRING;
 		$set_selected = SELECT_SET_STRING;
 	}