Squelch compiler warnings from connect.c

Forgot to include necessary header file to get the function declaration.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

connect.c

 #include "cache.h"
 #include "pkt-line.h"
 #include "quote.h"
+#include "refs.h"
 #include <sys/wait.h>
 #include <sys/socket.h>
 #include <netinet/in.h>