Support editors that use "atomic write"

Support editors that use "atomic write"

Some editors (like TextMate and at least my configuration of Vim) save
the file using an "atomic write".

They write the file to a new, temporary filename, and then rename the new
filename to the old filename. This assures that the file is never
"half-written" or corrupted in case of a crash.

The solicit() code didn't support this. By using seek() to rewind the
file pointer he was assuming that the editor was reusing the same inode.

Signed-off-by: Pedro Melo <melo@simplicidade.org>