Hi,

I've noticed that sometimes project-kill-buffers is noticeably slow, and
it seems like it's has to do with project--buffer-list working on remote
files. The function goes through every buffer and calls
(project-current), even if the buffer is related to a remote file that
cannot be part of the current project.

The patch I attach below is a simple fix to avoid checking files that
cannot be part of the current project. Or are there any edge-cases that
this code approach breaks?

-- 
	Philip K.