On linux, users can enter a ClearCase view either through the view root

(/view/<tag>/...) or with cleartool setview. In the setview case,

cleartool pwv -root returns an empty string, which we stored as the

root path of the view.
Every path in the generated diff (the diff headers, the DiffX

"path" fields, and the versionvault metadata) is computed with

os.path.relpath() against that root path. With an empty root path,

relpath() resolves against the current working directory instead,

producing paths like "../gui2/bin/clearcase/Xmakefile" that depend

entirely on where the user happened to run rbt.
The server can never resolve these, resulting in file-not-found errors

during diff validation. The same change would post fine for a user who

entered the view through /view/<tag>, which made the failures look

sporadic.
We now detect the empty result and use the filesystem root as the view

root. In a setview, VOBs appear directly under /, so this makes all

generated paths view-relative again, matching what a /view-based

workflow produces.

Added a unit test for get_local_path() in a setview context.
Ran unit tests.