Dataset->publish was not returning 'undef' when it couldn't update the
datastreams in fedora.
Took the 'search for a known ID' Fedora test out of the test module, and
updated tests 006 and 007 to allow for this.
Now removes the colon from Fedora IDs (XXX:nnn) before building data hosting
directories or URLs with them - since these will someday get built into zips,
and if they have colons they'll break when extracting under Windows.