Frameworks/base: Fix a hashCode implementation

Equals uses Arrays.equals. That means two responses are equal if
the content of the data arrays is equal. By convention, the hash
code of those objects should agree. In that case one cannot use
hashCode on the array (which is the identity hash code).

Change-Id: Icce8e2e71e9142421f5dac8a0ee8a211623fb704