Use assembly plugin 2.4, add missing ID.

guacamole-common-js/pom.xml

@@ -18,7 +18,9 @@
         <plugins>
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
+                <version>2.4</version>
                 <configuration>
+                    <appendAssemblyId>false</appendAssemblyId>
                     <descriptors>
                         <descriptor>static.xml</descriptor>
                     </descriptors>