maven_artifact: check whether snapshot is the latest snapshot

packaging/language/maven_artifact.py

@@ -339,7 +339,10 @@ def main():
     if os.path.isdir(dest):
         dest = dest + "/" + artifact_id + "-" + version + "." + extension
     if os.path.lexists(dest):
-        prev_state = "present"
+        if not artifact.is_snapshot():
+            prev_state = "present"
+        elif downloader.verify_md5(dest, downloader.find_uri_for_artifact(artifact) + '.md5'):
+            prev_state = "present"
     else:
         path = os.path.dirname(dest)
         if not os.path.exists(path):