Serializer-xml build fail when building with option '-DskipTests' fixed.

Change-Id: I635a5f619f691d7a9e1626f9cd780ed7d20e3a8d
diff --git a/serializers/xml/pom.xml b/serializers/xml/pom.xml
index 164e49b..2e19395 100644
--- a/serializers/xml/pom.xml
+++ b/serializers/xml/pom.xml
@@ -81,9 +81,15 @@
                         </goals>
                         <configuration>
                             <target>
-                                <delete>
+                                <delete includeemptydirs="true">
                                     <fileset dir="${project.build.outputDirectory}/org/onosproject/yang/gen" includes="**/*"/>
                                 </delete>
+                                <delete includeemptydirs="true">
+                                    <fileset dir="${project.build.outputDirectory}/yang" includes="**/*"/>
+                                </delete>
+                                <delete includeemptydirs="true" failonerror="false">
+                                    <fileset dir="${project.build.outputDirectory}/Temp" includes="**/*"/>
+                                </delete>
                             </target>
                         </configuration>
                     </execution>