Fix apparmor incorrectly denying access db tmp file.

This is /var/lib/mosquitto/mosquitto.db.new.

Closes #1978. Thanks to gnampf89.

ChangeLog.txt

@@ -5,6 +5,8 @@ Broker:
   Closes #1977.
 - Fix bridge connection not relinquishing POLLOUT after messages are sent.
   Closes #1979.
+- Fix apparmor incorrectly denying access to
+  /var/lib/mosquitto/mosquitto.db.new. Closes #1978.
 
 
 2.0.4 - 2020-12-22

security/mosquitto.apparmor

@@ -9,6 +9,7 @@
 	/etc/mosquitto/conf.d/* r,
 	/var/lib/mosquitto/ r,
 	/var/lib/mosquitto/mosquitto.db rwk,
+	/var/lib/mosquitto/mosquitto.db.new rwk,
 	/var/run/mosquitto.pid rw,
 
 	network inet stream,