Fix getRefsByPrefix usage Ie1b9ebd194a4ca2542d9aaf5c59c71dfbb361676 removed usage of the deprecated getRefs(PREFIX) API, but missed that the returned key was being used and the key had the prefix removed. Get ls-batches working correctly again by stripping the prefix from the returned Ref. Change-Id: I86784fdeb3a39e6d4ad44a75dcb57dd14c91db18