merge -r 788583 from 2.1.x branch 

[MNG-4189]
o compare the file's timestamp and size instead of using the resolved flag when resolving snapshots (fix by Benjamin Bentmann)
o added unit test


git-svn-id: https://svn.apache.org/repos/asf/maven/components/branches/maven-2.2.x@788596 13f79535-47bb-0310-9956-ffa450edef68
3 files changed