Handle incompatible record in Riak 1.4.0.

Return badrpc calls with an incompatible message when unable to
determine which versions of nodes are communicating in a mixed-
version cluster.

Switch to macros for record definitions.

Also, suppress information in the UI when detecting this incompatibility
to prevent from the display of NaN values.
Merge pull request #123 from basho/csm-1.4-bad-record-rebased

Handle incompatible record in Riak 1.4.0.