suppress maven warning

Change-Id: I922e21140b356048ba275fc825036e576d973324
diff --git a/tools/build/conf/pom.xml b/tools/build/conf/pom.xml
index c2ad09c..4865705 100644
--- a/tools/build/conf/pom.xml
+++ b/tools/build/conf/pom.xml
@@ -6,5 +6,10 @@
   <groupId>org.onlab.tools</groupId>
   <artifactId>onos-build-conf</artifactId>
   <version>1.0</version>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
 </project>