logrotate: preserve existing file owner/group/mode

wmtp and btmp are reliably created by systemd at boot with the proper
permissions which also means missingok can be dropped.

etc/logrotate.conf

@@ -27,11 +27,4 @@ tabooext + .pacorig .pacnew .pacsave
 # Arch packages drop log rotation information into this directory
 include /etc/logrotate.d
 
-/var/log/wtmp {
-    create 0664 root utmp
-}
-
-/var/log/btmp {
-    missingok
-    create 0600 root utmp
-}
+/var/log/wtmp /var/log/btmp {}

etc/logrotate.d/nginx

@@ -1,6 +1,5 @@
 /var/log/nginx/access.log /var/log/nginx/error.log {
     missingok
-    create 600 root root
     sharedscripts
     nodelaycompress
     maxsize 2G