error: Remove NULL checks on error_propagate() calls (again)

Patch created mechanically by rerunning:

    $ spatch --sp-file scripts/coccinelle/error_propagate_null.cocci \
             --macro-file scripts/cocci-macro-file.h \
             --use-gitgrep .

Cc: Jens Freimann <jfreimann@redhat.com>
Cc: Hailiang Zhang <zhang.zhanghailiang@huawei.com>
Cc: Juan Quintela <quintela@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200722084048.1726105-4-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

hw/net/virtio-net.c

@@ -817,9 +817,7 @@ static void failover_add_primary(VirtIONet *n, Error **errp)
             "sure primary device has parameter"
             " failover_pair_id=<virtio-net-id>\n");
 }
-    if (err) {
-        error_propagate(errp, err);
-    }
+    error_propagate(errp, err);
 }
 
 static int is_my_primary(void *opaque, QemuOpts *opts, Error **errp)
@@ -873,9 +871,7 @@ static DeviceState *virtio_connect_failover_devices(VirtIONet *n,
         n->primary_device_id = g_strdup(prim_dev->id);
         n->primary_device_opts = prim_dev->opts;
     } else {
-        if (err) {
-            error_propagate(errp, err);
-        }
+        error_propagate(errp, err);
     }
 
     return prim_dev;

migration/colo.c

@@ -798,9 +798,7 @@ static void colo_incoming_process_checkpoint(MigrationIncomingState *mis,
 
     colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
                  &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-    }
+    error_propagate(errp, local_err);
 }
 
 static void colo_wait_handle_message(MigrationIncomingState *mis,

migration/migration.c

@@ -623,9 +623,7 @@ void migration_fd_process_incoming(QEMUFile *f, Error **errp)
     }
 
     if (migration_incoming_setup(f, &local_err)) {
-        if (local_err) {
-            error_propagate(errp, local_err);
-        }
+        error_propagate(errp, local_err);
         return;
     }
     migration_incoming_process();
@@ -647,9 +645,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
         }
 
         if (migration_incoming_setup(f, &local_err)) {
-            if (local_err) {
-                error_propagate(errp, local_err);
-            }
+            error_propagate(errp, local_err);
             return;
         }