Fix Zebra server not starting

files/etc/s6-overlay/s6-rc.d/zebra-server/run

@@ -1,6 +1,14 @@
 #!/command/execlineb -P
+with-contenv
+
+importas -D "" elastic USE_ELASTICSEARCH
+
+if -n { test "${elastic}" = "true" }
+
 fdmove -c 2 1
 
+s6-envdir /etc/koha-envvars
+
 s6-setuidgid default-koha
 
 /usr/bin/zebrasrv -v 1 -f /etc/koha/sites/default/koha-conf.xml