Fix for bug 232447: Warns user about missing bug number instead of dying in GetBugLink().

r=justdave

webtools/bugzilla/globals.pl

@@ -1007,7 +1007,8 @@ sub GetAttachmentLink {
 
 sub GetBugLink {
     my ($bug_num, $link_text, $comment_num) = @_;
-    detaint_natural($bug_num) || die "GetBugLink() called with non-integer bug number";
+    $bug_num || return "<missing bug number>";
+    detaint_natural($bug_num) || return "<invalid bug number>";
 
     # If we've run GetBugLink() for this bug number before, %::buglink
     # will contain an anonymous array ref of relevent values, if not