Added default, empty init target, and fixed a bug in set-version target.

jdb-build-1.6.xml

@@ -52,6 +52,8 @@
             classname="org.codehaus.groovy.ant.Groovy"/>
     </target>
 
+    <target name="init"/>
+
     <target name="clean" depends="-init">
         <delete dir="${build.dir}"/>
     </target>
@@ -89,6 +91,7 @@
         <propertyfile file="${versioning.file}">
             <entry key="version" value="${new-version}" operation="="
                 type="string"/>
+            <entry key="build.number" value="0" type="int" operation="="/>
         </propertyfile>
     </target>