Improve logrotate configuration file

- Avoid changing file permissions
- Make sure all log files are reopened
- Remove non-sense prerotate script
- Send SIGUSR1 to all nghttpx processes

contrib/nghttpx-logrotate

@@ -1,18 +1,11 @@
 /var/log/nghttpx/*.log {
-        weekly
+  weekly
-        missingok
+  rotate 52
-        rotate 52
+  missingok
-        compress
+  compress
-        delaycompress
+  delaycompress
-        notifempty
+  notifempty
-        create 0640 www-data adm
+  postrotate
-        sharedscripts
+    killall -USR1 nghttpx 2> /dev/null || true
-        prerotate
+  endscript
-                if [ -d /etc/logrotate.d/httpd-prerotate ]; then \
-                        run-parts /etc/logrotate.d/httpd-prerotate; \
-                fi \
-        endscript
-        postrotate
-                [ -s /run/nghttpx.pid ] && kill -USR1 `cat /run/nghttpx.pid`
-        endscript
 }