improve missing repository error message

Certain remote commands, when asked to do something in a
particular directory that was not actually a git repository,
would say "unable to chdir or not a git archive". The
"chdir" bit is an unnecessary detail, and the term "git
archive" is much less common these days than "git repository".

So let's switch them all to:

  fatal: '%s' does not appear to be a git repository

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon.c

@@ -229,7 +229,7 @@ static char *path_ok(char *directory)
 	}
 
 	if (!path) {
-		logerror("'%s': unable to chdir or not a git archive", dir);
+		logerror("'%s' does not appear to be a git repository", dir);
 		return NULL;
 	}