Revert checksum to what the port had previously due to a report of breakage.

There is something strange going on here. Maybe with the way Github makes
these archives?
In r463680 we had for the same file/same git hash:
SHA256 (ceph-ceph-erasure-code-corpus-2d7d78b_GH0.tar.gz) = 466f7185015df8d13f8b2b9a17ee30ab419bcd667284ce2b6d32a1128c4640f1
SIZE (ceph-ceph-erasure-code-corpus-2d7d78b_GH0.tar.gz) = 3634266

Then in r474922 it was changed to:
SHA256 (ceph-ceph-erasure-code-corpus-2d7d78b_GH0.tar.gz) = 8ab8f36f3e0a720c882b8bb4abb3f2e26bd6b025cc263119207f7d2eb3b1e490
SIZE (ceph-ceph-erasure-code-corpus-2d7d78b_GH0.tar.gz) = 3685656

When I was working on this port the 8ab8f36 checksum failed, but the 466f718
checksum worked, so I changed back in r477944. Now it seems the 8ab8f36
checksum is working and 466f718 is not.

I have both files. Both are identical when extracted. The only difference
appears to be the compression ratio. As of right now I can only download
the 8ab8f36 file.

Reported by: fluffy