Rotate langpack logs

debian/custom-site-mahara-langpacks.logrotate

+/var/log/mahara-langpacks/langpacks.log {
+    weekly
+    missingok
+    rotate 52
+    compress
+    delaycompress
+    notifempty
+    create 640 maharabot maharabot
+}
+/var/log/mahara-langpacks/update-pot.log {
+    weekly
+    missingok
+    rotate 52
+    compress
+    delaycompress
+    notifempty
+    create 640 maharabot maharabot
+}

debian/rules

@@ -21,6 +21,7 @@ binary:
 	dh_install
 	dh_installdirs
 	dh_installcron
+	dh_installlogrotate
 	dh_gencontrol
 	dh_md5sums
 	dh_builddeb