Revert "Merge pull request #74 from schomatis/fix/sum/id-hash-len"
Revert "Merge pull request #74 from schomatis/fix/sum/id-hash-len"

This reverts commit 77e05121b6a64ea180e5336a4466d05221e91aa3, reversing
changes made to 265e72146e710ff649c6982e3699d01d4e9a18bb.

jbenet/go-multihash,jbenet/go-multihash