Bumping The Fork to 1.2.8

@ericchang: I need to upgrade our `kiji-mapreduce` fork because I had to upgrade `kiji-schema` to a recent release for `kiji-scoring` (which I'll post the PR for the fork in a few minutes) that needed a recent `kiji-schema`. Some `Hbase`-specific `impl` classes referenced by `kiji-mapreduce` have now moved from `..impl.` to `..impl.hbase`, forcing me to go with the upgrade on the trio.