MINOR: listener/api: add lli hint to listener functions

MINOR: listener/api: add lli hint to listener functions

Add listener lock hint (AKA lli) to (stop/resume/pause)_listener() functions.
All these functions implicitely take the listener lock when they are called:
It could be useful to be able to call them while already holding the lock, so
we're adding lli hint to make them take the lock only when it is missing.

This should only be backported if explicitly required by another commit
--

-> 2.4 and 2.5 common backport notes:

These 2 commits need to be backported first:
 - 187396e34 "CLEANUP: listener: function comment typo in stop_listener()"
 - a57786e87 "BUG/MINOR: listener: null pointer dereference suspected by
   coverity"

-> 2.4 special backport notes:

In addition to the previously mentionned dependencies, the patch needs to be
slightly adapted to match the corresponding contextual lines:

Replace this:

    |@@ -471,7 +474,8 @@ int pause_listener(struct listener *l, int lpx)
    |        if (!lpx && px)
    |                HA_RWLOCK_WRLOCK(PROXY_LOCK, &px->lock);
    |
    |-       HA_RWLOCK_WRLOCK(LISTENER_LOCK, &l->lock);
    |+       if (!lli)
    |+               HA_RWLOCK_WRLOCK(LISTENER_LOCK, &l->lock);
    |
    |        if (l->state <= LI_PAUSED)
    |                goto end;

By this:

    |@@ -471,7 +474,8 @@ int pause_listener(struct listener *l, int lpx)
    |        if (!lpx && px)
    |                HA_RWLOCK_WRLOCK(PROXY_LOCK, &px->lock);
    |
    |-       HA_RWLOCK_WRLOCK(LISTENER_LOCK, &l->lock);
    |+       if (!lli)
    |+               HA_RWLOCK_WRLOCK(LISTENER_LOCK, &l->lock);
    |
    |        if ((global.mode & (MODE_DAEMON | MODE_MWORKER)) &&
    |            !(proc_mask(l->rx.settings->bind_proc) & pid_bit))

Replace this:

    |@@ -169,7 +169,7 @@ void protocol_stop_now(void)
    |        HA_SPIN_LOCK(PROTO_LOCK, &proto_lock);
    |        list_for_each_entry(proto, &protocols, list) {
    |                list_for_each_entry_safe(listener, lback, &proto->receivers, rx.proto_list)
    |-                       stop_listener(listener, 0, 1);
    |+                       stop_listener(listener, 0, 1, 0);
    |        }
    |        HA_SPIN_UNLOCK(PROTO_LOCK, &proto_lock);
    | }

By this:

    |@@ -169,7 +169,7 @@ void protocol_stop_now(void)
    |        HA_SPIN_LOCK(PROTO_LOCK, &proto_lock);
    |        list_for_each_entry(proto, &protocols, list) {
    |                list_for_each_entry_safe(listener, lback, &proto->receivers, rx.proto_list)
    |                        if (!listener->bind_conf->frontend->grace)
    |-                               stop_listener(listener, 0, 1);
    |+                               stop_listener(listener, 0, 1, 0);
    |        }
    |        HA_SPIN_UNLOCK(PROTO_LOCK, &proto_lock);

Replace this:

    |@@ -2315,7 +2315,7 @@ void stop_proxy(struct proxy *p)
    |        HA_RWLOCK_WRLOCK(PROXY_LOCK, &p->lock);
    |
    |        list_for_each_entry(l, &p->conf.listeners, by_fe)
    |-               stop_listener(l, 1, 0);
    |+               stop_listener(l, 1, 0, 0);
    |
    |        if (!(p->flags & (PR_FL_DISABLED|PR_FL_STOPPED)) && !p->li_ready) {
    |                /* might be just a backend */

By this:

    |@@ -2315,7 +2315,7 @@ void stop_proxy(struct proxy *p)
    |        HA_RWLOCK_WRLOCK(PROXY_LOCK, &p->lock);
    |
    |        list_for_each_entry(l, &p->conf.listeners, by_fe)
    |-               stop_listener(l, 1, 0);
    |+               stop_listener(l, 1, 0, 0);
    |
    |        if (!p->disabled && !p->li_ready) {
    |                /* might be just a backend */