At the moment, "wide find file" feature (M-f) doesn't work on remote directories (e.g. on /ssh:myserver:/some/directory it finds nothing in any case).
This commit is intended to fix the problem:
- We test if a directory are remote (file-remote-p), and if it is, we correct directory path (remove specific prefix), since the path should be passed to "find" program at remote server
- We also explicitly set working directory since we should run the "find" command on remote server, and our current working directory may be local