bundle: Use full system path for bundle dir

When reading a bundle from a directory we should be using the full
system path for the module files. This helps greatly with reducing
complexity of trying to read error messages. It also makes the
integration with tools like VSCode work better as they can provide
links from the console output file paths to the file in question.

This will not affect bundles loaded from tarballs.

Fixes: #1796
Signed-off-by: Patrick East <east.patrick@gmail.com>