bug#10124: 24.0.91; Choosing a remote file, when the current directory is remote too

[Dani Moncayo <dmoncayo@gmail.com>]

Recipe from "emacs -Q":

1. Eval: (cd "/usr@host:/path-0/").
2. Eval: (diff "/usr@host:/path-1/file-1" "/usr@host:/path-2/file-2")
3. In the *Diff* buffer, move point to a hunk and type "C-c C-c".
4. In the "Use file" prompt, accept the default (i.e., just type RET).

--> Expected result: File "/usr@host:/path-2/file-2" is visited.
--> Observed result: A *Completions* buffer is created.


Notes:
* "usr@host" stands for a user account in a remote host.
* "path-<n>" stands for valid directories (in that remote host).
* "file-1" and "file-2" stands for valid files that are not equal.


In GNU Emacs 24.0.91.1 (i386-mingw-nt5.1.2600)
 of 2011-11-22 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.6) --no-opt --cflags
-ID:/devel/emacs/libs/libXpm-3.5.8/include
-ID:/devel/emacs/libs/libXpm-3.5.8/src
-ID:/devel/emacs/libs/libpng-dev_1.4.3-1/include
-ID:/devel/emacs/libs/zlib-dev_1.2.5-2/include
-ID:/devel/emacs/libs/giflib-4.1.4-1/include
-ID:/devel/emacs/libs/jpeg-6b-4/include
-ID:/devel/emacs/libs/tiff-3.8.2-1/include
-ID:/devel/emacs/libs/gnutls-2.10.1/include --ldflags
-LD:/devel/emacs/libs/gnutls-2.10.1/lib'

-- 
Dani Moncayo