fixed some system tests as we changed the example api method

tests/PHPUnit/System/expected/test_ImportLogs__ExamplePlugin.getExampleReport_month.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <result>
 	<row>
+		<label>My Label 1</label>
+		<nb_visits>1</nb_visits>
+	</row>
+	<row>
+		<label>My Label 2</label>
 		<nb_visits>5</nb_visits>
 	</row>
 </result>
\ No newline at end of file

tests/PHPUnit/System/expected/test_OneVisitorTwoVisits__ExamplePlugin.getExampleReport_day.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <result>
 	<row>
+		<label>My Label 1</label>
+		<nb_visits>1</nb_visits>
+	</row>
+	<row>
+		<label>My Label 2</label>
 		<nb_visits>5</nb_visits>
 	</row>
 </result>
\ No newline at end of file

tests/PHPUnit/System/expected/test_noVisit_PeriodIsLast__ExamplePlugin.getExampleReport_day.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <result>
 	<row>
+		<label>My Label 1</label>
+		<nb_visits>1</nb_visits>
+	</row>
+	<row>
+		<label>My Label 2</label>
 		<nb_visits>5</nb_visits>
 	</row>
 </result>
\ No newline at end of file

tests/PHPUnit/System/expected/test_noVisit_PeriodIsLast__ExamplePlugin.getExampleReport_week.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <result>
 	<row>
+		<label>My Label 1</label>
+		<nb_visits>1</nb_visits>
+	</row>
+	<row>
+		<label>My Label 2</label>
 		<nb_visits>5</nb_visits>
 	</row>
 </result>
\ No newline at end of file

tests/PHPUnit/System/expected/test_noVisit__ExamplePlugin.getExampleReport_day.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <result>
 	<row>
+		<label>My Label 1</label>
+		<nb_visits>1</nb_visits>
+	</row>
+	<row>
+		<label>My Label 2</label>
 		<nb_visits>5</nb_visits>
 	</row>
 </result>
\ No newline at end of file