qemu: Fix Coverity build for qemu_monitor

Commit id '7ef0471b' added a new parameter to qemuMonitorOpen,
but didn't update the ATTTRIBUTE_NONNULL for the @CB (param 5).
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NKaterina Koukiou <kkoukiou@redhat.com>

src/qemu/qemu_monitor.h

@@ -317,7 +317,7 @@ qemuMonitorPtr qemuMonitorOpen(virDomainObjPtr vm,
                                unsigned long long timeout,
                                qemuMonitorCallbacksPtr cb,
                                void *opaque)
-    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(5);
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(6);
 qemuMonitorPtr qemuMonitorOpenFD(virDomainObjPtr vm,
                                  int sockfd,
                                  bool json,