437438 implementation and unittest of the release redeploy bugfix

- checks if the master repository is a MavenRepository for RELEASE artifacts and with WRITE (REDEPLOY) policy
- compares timestamps to update cache if necessary
- see UnzipCacheTest.testReleaseRedeploy for a testcase
- RepositoryMock has a new inner subclass MavenRepositoryMock which implements the MavenRepository interface

Bug: 437438
Signed-off-by: hardi.probst@gmail.com