transmat/impl/tar: mirror check for hashmismatch.
transmat/impl/tar: mirror check for hashmismatch.

After all that work we went through to ensure the IO stream is split and hashed again, we'd better actually check it, eh?

Signed-off-by: Eric Myhre <2346ad27d7568ba9896f1b7da6b5991251debdf2@exultant.us>

polydawn/rio,polydawn/rio