Revision 216013

Fixing problem with using distributionManagement repository definition for download of plugins.xml metadata.

Now, in order to build a maven plugin, you need two things:

1. a repository defined in distributionManagment
2. a repository defined in <repositories/> which has the same id as the one in distributionManagement.

This is necessary, since in most cases SSH will be used in the distributionManagement definition for uploading the plugin...which means that the download of the existing plugins.xml file might not be available for users trying to run an install. SSH requires authentication information, and users (particularly those running the bootstrap) might not have this auth info.