When the repository type is MAVEN_SNAPSHOT, the artifact is downloaded
from the Maven snapshot repository [1].
The artifact ID is given in the form:
group:name:version:snapshot
where `group`, `name` and `version` are as before, and `snapshot` is
the snapshot timestamp (i.e. '20160407.201829-175').
[1] https://oss.sonatype.org/content/repositories/snapshots/
Change-Id: I992eb1461aa976ccc5137669270abe704f260500
777cd1a926