copy sieve using cp instead of rsync

src/mailsrv/assets/bin/mkvirt

@@ -25,7 +25,8 @@ postmap aliases
 # copy users sieve to mail
 cd /vol/db/sieve.d
 for user in * ; do
-  rsync -vaSH ${user} /vol/mail/${user}/.dovecot.sieve
+  mkdir -p /vol/mail/${user}
+  chown vmail:vmail /vol/mail/${user}
+  chown vmail:vmail ${user}
+  cp -p ${user} /vol/mail/${user}/.dovecot.sieve
 done
-
-chown -R vmail:vmail /vol/mail