build: suppress warnings from FindBugs to fix build on Travis CI.

Correction for 8018e6a commit.

Author: php-coder

src/main/config/findbugs-filter.xml

@@ -20,6 +20,14 @@
 		<Class name="ru.mystamps.web.feature.image.ImageDto" />
 		<Bug pattern="EI_EXPOSE_REP,EI_EXPOSE_REP2" />
 	</Match>
+	<Match>
+		<Class name="ru.mystamps.web.feature.series.AddSeriesSalesForm" />
+		<Or>
+			<Method name="getDate" />
+			<Method name="setDate" />
+		</Or>
+		<Bug pattern="EI_EXPOSE_REP,EI_EXPOSE_REP2" />
+	</Match>
 	<Match>
 		<!--
 			String[] allowedContentTypes: potentially caller can modify data after passing it to the