try to make the IT pass on Windows

git-svn-id: https://svn.apache.org/repos/asf/maven/plugin-tools/trunk@1599269 13f79535-47bb-0310-9956-ffa450edef68
[MPLUGIN-267] document how to change desriptor phase instead of running it twice with skipErrorNoDescriptorsFound

git-svn-id: https://svn.apache.org/repos/asf/maven/plugin-tools/trunk@1599273 13f79535-47bb-0310-9956-ffa450edef68