Remove deprecated single descriptor and move to multi descriptors whi…

…ch is not deprecated

It will allow to upgrade maven assembly descriptor

Change-Id: I11fb19428ce484457074fa7c8a7b4ad7a5c5653f
Signed-off-by: Florent BENOIT <fbenoit@redhat.com>

assembly/assembly-wsagent-server/pom.xml

@@ -75,7 +75,9 @@
                     <tarLongFileMode>posix</tarLongFileMode>
                     <appendAssemblyId>false</appendAssemblyId>
                     <updateOnly>false</updateOnly>
-                    <descriptor>${project.basedir}/src/assembly/assembly.xml</descriptor>
+                    <descriptors>
+                        <descriptor>${project.basedir}/src/assembly/assembly.xml</descriptor>
+                    </descriptors>
                     <finalName>ext-server-${project.version}</finalName>
                 </configuration>
             </plugin>