Test fix.
fixes #1019
removed the optimization: putting evictable null when mapstore.load() returns null
users can easily add such optimization to their mapstore implementation.
meanwhile internal optimization causes bugs
Merge pull request #1021 from enesakar/maint/fix1019

fixes #1019
Fixes #1024
Typo.
Merge pull request #1025 from mdogan/fix/3.1/1024

Fixes #1024
Merge branch 'maintenance-3.x' of github.com:hazelcast/hazelcast into fix/3.x/multi-map-migration
small fix for backward compatibility