Fix #877346.

debian/changelog

@@ -4,6 +4,7 @@ mosquitto (1.5.4-2) unstable; urgency=medium
     (Closes: #914525)
     - This is needed to allow compilation on non-Linux systems.
   * Fix FTCBFS: Let dh_auto_build pass cross tools to make. (Closes: #914593)
+  * Ensure log files are owned by mosquitto. (Closes: #877346)
 
  -- Roger A. Light <roger@atchoo.org>  Sun, 25 Nov 2018 13:52:16 +0000
 

debian/mosquitto.postinst

@@ -17,7 +17,7 @@ setup_mosquitto_user() {
 
 fix_permissions() {
 	chown mosquitto /var/lib/mosquitto
-	chown mosquitto /var/log/mosquitto
+	chown mosquitto /var/log/mosquitto /var/log/mosquitto/mosquitto.log
 }
 
 case "$1" in