tests/test-clone-failure.out

windows: provide filename in IOError exceptions

This brings the Windows posixfile errors in line with the errors
on other platforms.

abort: repository a not found!
255
abort: error: Connection refused
255
abort: repository a not found!
255
abort: Permission denied: ../a
255
abort: repository a not found!
255
destination directory: q
abort: destination 'q' is not empty
abort: destination 'a' is not empty
255
adding c
255
dir is still here
repo is gone