lib: Allow zclient do-over of connect on initial attempt

When a protocol is attempting to connect to the zebra daemon
through it's socket.  If the inital attempt fails, give it a
few more attempts before giving up and leaving the daemon in
a bizarre state.

This problem was found by Ashley Penney, and Ashley was of
immense help in debugging and testing the fix for this issue.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Tested-by: Ashley Penney <apenney@ntoggle.com>
Tested-by: NetDEF CI System <cisystem@netdef.org>
diff --git a/lib/zclient.c b/lib/zclient.c
index 9d50ebc..208ea5c 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -181,6 +181,7 @@
   ret = connect (sock, (struct sockaddr *) &serv, sizeof (serv));
   if (ret < 0)
     {
+      zlog_warn ("%s connect failure: %d", __PRETTY_FUNCTION__, errno);
       close (sock);
       return -1;
     }
@@ -216,6 +217,7 @@
   ret = connect (sock, (struct sockaddr *) &addr, len);
   if (ret < 0)
     {
+      zlog_warn ("%s connect failure: %d", __PRETTY_FUNCTION__, errno);
       close (sock);
       return -1;
     }
@@ -429,11 +431,23 @@
   if (zclient->t_connect)
     return 0;
 
-  if (zclient_socket_connect(zclient) < 0)
+  /*
+   * If we fail to connect to the socket on initialization,
+   * Let's wait a second and see if we can reconnect.
+   * Cause if we don't connect, we never attempt to
+   * reconnect.  On startup if zebra is slow we
+   * can get into this situation.
+   */
+  while (zclient_socket_connect(zclient) < 0 && zclient->fail < 5)
     {
       if (zclient_debug)
 	zlog_debug ("zclient connection fail");
       zclient->fail++;
+      sleep (1);
+    }
+
+  if (zclient->sock < 0)
+    {
       zclient_event (ZCLIENT_CONNECT, zclient);
       return -1;
     }