CLEANUP: Stop checking the pointer before calling `task_free()`

Changes performed with this Coccinelle patch:

    @@
    expression e;
    @@

    - if (e != NULL) {
    	task_destroy(e);
    - }

    @@
    expression e;
    @@

    - if (e) {
    	task_destroy(e);
    - }

    @@
    expression e;
    @@

    - if (e)
    	task_destroy(e);

    @@
    expression e;
    @@

    - if (e != NULL)
    	task_destroy(e);
diff --git a/src/connection.c b/src/connection.c
index 29197ad..f8a0a42 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -2451,8 +2451,7 @@
 	int i;
 
 	for (i = 0; i < global.nbthread; i++) {
-		if (idle_conns[i].cleanup_task)
-			task_destroy(idle_conns[i].cleanup_task);
+		task_destroy(idle_conns[i].cleanup_task);
 	}
 }
 REGISTER_POST_DEINIT(deinit_idle_conns);
diff --git a/src/dns.c b/src/dns.c
index b103c86..8855f37 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -779,8 +779,7 @@
 {
 	pool_free(dns_msg_buf, ds->rx_msg.area);
 	pool_free(dns_msg_buf, ds->tx_ring_area);
-	if (ds->task_exp)
-		task_destroy(ds->task_exp);
+	task_destroy(ds->task_exp);
 
 	dns_queries_flush(ds);
 
@@ -1080,8 +1079,7 @@
 	return ds;
 
 error:
-	if (ds->task_exp)
-		task_destroy(ds->task_exp);
+	task_destroy(ds->task_exp);
 	pool_free(dns_msg_buf, ds->rx_msg.area);
 	pool_free(dns_msg_buf, ds->tx_ring_area);
 
diff --git a/src/hlua.c b/src/hlua.c
index 5c29bc5..a758f62 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -9257,8 +9257,7 @@
 
  mem_error:
 	if (hlua_sub) {
-		if (hlua_sub->task)
-			task_destroy(hlua_sub->task);
+		task_destroy(hlua_sub->task);
 		if (hlua_sub->hlua)
 			hlua_ctx_destroy(hlua_sub->hlua);
 		pool_free(pool_head_hlua_event_sub, hlua_sub);
diff --git a/src/mworker.c b/src/mworker.c
index 11d61a2..b1115cc 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -502,8 +502,7 @@
 		/* disable this peer section so that it kills itself */
 		if (curpeers->sighandler)
 			signal_unregister_handler(curpeers->sighandler);
-		if (curpeers->sync_task)
-			task_destroy(curpeers->sync_task);
+		task_destroy(curpeers->sync_task);
 		curpeers->sync_task = NULL;
 		curpeers->peers_fe = NULL;
 	}
diff --git a/src/resolvers.c b/src/resolvers.c
index a3f328d..ee70e45 100644
--- a/src/resolvers.c
+++ b/src/resolvers.c
@@ -2491,10 +2491,8 @@
 		if (ns->stream) {
 			if (ns->stream->ring_req)
 				ring_free(ns->stream->ring_req);
-			if (ns->stream->task_req)
-				task_destroy(ns->stream->task_req);
-			if (ns->stream->task_rsp)
-				task_destroy(ns->stream->task_rsp);
+			task_destroy(ns->stream->task_req);
+			task_destroy(ns->stream->task_rsp);
 			free(ns->stream);
 		}
 		LIST_DEL_INIT(&ns->list);