Clarify error response from 'git fetch' for bad responses

This error message prints the reponse from the server at this point.
Label it as such in the output.

Signed-off-by: Sam Vilain <sam@vilain.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

walker.c

@@ -274,7 +274,7 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 
 	for (i = 0; i < targets; i++) {
 		if (interpret_target(walker, target[i], &sha1[20 * i])) {
-			error("Could not interpret %s as something to pull", target[i]);
+			error("Could not interpret response from server '%s' as something to pull", target[i]);
 			goto unlock_and_fail;
 		}
 		if (process(walker, lookup_unknown_object(&sha1[20 * i])))