added missing repository configuration for ROO dependencies.

This repository is required when a SNAPSHOT version of ROO dependencies is used. For example create a project as follows:

    project --projectName primefaces-cookbook-roo --topLevelPackage org.primefaces.cookbook
    persistence setup --provider HIBERNATE --database HYPERSONIC_IN_MEMORY 
    web jsf setup --implementation APACHE_MYFACES --library PRIMEFACES --theme EGGPLANT 
    web jsf all --package org.primefaces.cookbook

Then run:

    mvn jetty:run

Maven complains that it cannot find `org.springframework.roo.annotations:jar:1.2.5.BUILD-SNAPSHOT`. This is because ROO depedencies version is updated to a SNAPSHOT version but corresponding repository is not added to the template.