Bump version to 2.7-cloudtm-SNAPSHOT
Fix Infinispan version

It got skewed when bumping the FF to the next snapshot version.
Support setting B+Tree LOWER_BOUND via configuration

  Use config property 'btreeLowerBound'.  This affects both BPlusTree and
  BPlusTreeArray implementations.
Prepare release 2.7-cloudtm
Merge branch 'release/2.7-cloudtm' into cloudtm/master