Temporary workaround for existing /OMERO/Pixels

Imports were appearing corrupted since the ROMIO
layer was finding pixel files with equivalent ids
under /OMERO/Pixels despite the fact that "target"
was set on the pixels object. Here, the resolver
(OmeroFilePathResolver.java) has been updated to
count any repo value as being local. This will break
certain FS usage patterns, but this will be fixed
before release.

At the same time the uuid is now being properly
propagated to the pixels object. This should really
be a concern of the repository object itself, and
so this code path too will need refactoring.