rconn: Suppress 'connected' log for unreliable connections.

Recent assertion failure fix changed rconn workflow for unreliable
connections (such as connections from ovs-ofctl) from

    |rconn|DBG|br-int<->unix#151: entering ACTIVE
    |rconn|DBG|br-int<->unix#151: connection closed by peer
    |rconn|DBG|br-int<->unix#151: entering DISCONNECTED

To

    |rconn|DBG|br-int<->unix#200: entering CONNECTING
    |rconn|INFO|br-int<->unix#200: connected
    |rconn|DBG|br-int<->unix#200: entering ACTIVE
    |rconn|DBG|br-int<->unix#200: connection closed by peer
    |rconn|DBG|br-int<->unix#200: entering DISCONNECTED

Many monitoring/configuring tools (ex. ovs-neutron-agent) uses
ovs-ofctl frequently to check the statuses of installed flows.
This produces a lot of "connected" logs, that are useless in general.

Fix that by changing the log level to DBG for unreliable connections.

Suggested-by: Ben Pfaff <blp@ovn.org>
Fixes: c9a9b9b ("rconn: Introduce new invariant to fix assertion failure in corner case.")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

lib/rconn.c

@@ -498,7 +498,7 @@ run_CONNECTING(struct rconn *rc)
 {
     int retval = vconn_connect(rc->vconn);
     if (!retval) {
-        VLOG_INFO("%s: connected", rc->name);
+        VLOG(rc->reliable ? VLL_INFO : VLL_DBG, "%s: connected", rc->name);
         rc->n_successful_connections++;
         state_transition(rc, S_ACTIVE);
         rc->version = vconn_get_version(rc->vconn);