Fixed usage of Identical validator with fieldsets
Fixed issue when top level key doesn't exist in context
Merge branch 'fix-identical-validator' of git://github.com/wryck7/zf2 into hotfix/3803
[#3803] Remove BC break

- Removed "array" typehint from $context; added check within method body
Merge branch 'hotfix/3803'

Close #3803