Add missing `break'.
Add missing `break'.

Fixes a bug where we'd convert FP data to 12 bit, and then try to
convert it as double precision data.

git-svn-id: 83c4c97093aeea62ac982fbfd516bf9db27f5c99@971 c36c8488-0289-0348-9b64-b301f74bd9a7

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok