Put the \001 prefix back on scp error messages when they're sent to

the server. (Not sure _why_ they're sent to the server; scp is
weird.) It may be pointless when sent to the screen, which is why I
removed it, but it's extremely pointful on the wire :-(

[originally from svn r1090]

scp.c

@@ -616,6 +616,7 @@ static void run_err(const char *fmt, ...)
     strcpy(str, "scp: ");
     vsprintf(str+strlen(str), fmt, ap);
     strcat(str, "\n");
+    back->send("\001", 1);	       /* scp protocol error prefix */
     back->send(str, strlen(str));
     tell_user(stderr, "%s",str);
     va_end(ap);