curl_multi_cleanup: ignore SIGPIPE better

When looping and closing each individual connection left open, the
SIGPIPE ignoring was not done and could thus lead to death by signal 13.

Bug: http://thread.gmane.org/gmane.comp.version-control.git/238242

lib/multi.c

@@ -1806,10 +1806,13 @@ static void close_all_connections(struct Curl_multi *multi)
 
   conn = Curl_conncache_find_first_connection(multi->conn_cache);
   while(conn) {
+    SIGPIPE_VARIABLE(pipe_st);
     conn->data = multi->closure_handle;
 
+    sigpipe_ignore(conn->data, &pipe_st);
     /* This will remove the connection from the cache */
     (void)Curl_disconnect(conn, FALSE);
+    sigpipe_restore(&pipe_st);
 
     conn = Curl_conncache_find_first_connection(multi->conn_cache);
   }