Minor update to checkRemoveSeries() to ensure that the removed

SeriesProviders are unique.

Signed-off-by: Jordan Deyton <deytonjh@ornl.gov>

tests/org.eclipse.ice.viz.test/src/org/eclipse/ice/viz/plotviewer/test/PlotProviderTester.java

@@ -108,7 +108,9 @@ public void checkRemoveSeries() {
 		// Series and times to add and later *remove*. Each series is added for
 		// each time, resulting in 4 total additions.
 		SeriesProvider series1 = new SeriesProvider();
+		series1.setSeriesTitle("series1");
 		SeriesProvider series2 = new SeriesProvider();
+		series2.setSeriesTitle("series2");
 		double time1 = 42.0;
 		double time2 = 343.1337;