Fix no compression bug.
Fix no compression bug.

Two separate issues: 1) I'd stupidly left some debugging code in
there.  2) We need to compress data *before* we write the header,
or else the header will always write that the data are
uncompressed.

git-svn-id: 353be9ac11a1e711854a13efcc2fc17d9d6b83e7@1923 c36c8488-0289-0348-9b64-b301f74bd9a7

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok