[NEXUS-4766] Use classifier/extension from existing maven metadata if available

This will force using the classifier/extension that was uploaded by maven, which is correct in case of classifiers with dots

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-4766] Add UT for regenerating metadata for artefacts with a classifier with dots

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge remote-tracking branch 'origin/master' into nexus-4766-classifier-with-dots
Merge remote-tracking branch 'origin/master' into nexus-4766-classifier-with-dots
[NEXUS-4766] Avoid reading old metadata multiple times

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge pull request #27 from sonatype/nexus-4766-classifier-with-dots

REVIEW: [NEXUS-4766] Use classifier/extension from existing maven metadata if available