qemu: Make qemuMonitorSetMigrationCompression saner

Checking whether the function has anything to do is better done in the
function rather then requiring callers to do that.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_migration.c

@@ -3455,8 +3455,7 @@ qemuMigrationSetCompression(virQEMUDriverPtr driver,
     if (qemuDomainObjEnterMonitorAsync(driver, vm, job) < 0)
         return -1;
 
-    if ((params->level_set || params->threads_set || params->dthreads_set) &&
-        qemuMonitorSetMigrationCompression(priv->mon, params) < 0)
+    if (qemuMonitorSetMigrationCompression(priv->mon, params) < 0)
         goto cleanup;
 
     if (compression->xbzrle_cache_set &&

src/qemu/qemu_monitor.c

@@ -2177,6 +2177,11 @@ qemuMonitorSetMigrationCompression(qemuMonitorPtr mon,
 
     QEMU_CHECK_MONITOR_JSON(mon);
 
+    if (!compress->level_set &&
+        !compress->threads_set &&
+        !compress->dthreads_set)
+        return 0;
+
     return qemuMonitorJSONSetMigrationCompression(mon, compress);
 }