Bug 289627: Chart report crashes when there is no series data to plot - Patch by Frédéric Buclin <LpSolit@gmail.com> r=gerv a=LpSolit

git-svn-id: svn://10.0.0.236/trunk@220560 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/webtools/bugzilla/Bugzilla/Chart.pm

@@ -218,6 +218,8 @@ sub readData {
     # We need to handle errors better.
     my $series_ids = join(",", $self->getSeriesIDs());
 
+    return [] unless $series_ids;
+
     # Work out the date boundaries for our data.
     my $dbh = Bugzilla->dbh;