glusterfs service: Ensure dirs needed by `glusterfind` exist

nixos/modules/services/network-filesystems/glusterfs.nix

@@ -50,11 +50,19 @@ in
       after = [ "rpcbind.service" "network.target" "local-fs.target" ];
       before = [ "network-online.target" ];
 
-      # The copying of hooks is due to upstream bug https://bugzilla.redhat.com/show_bug.cgi?id=1452761
       preStart = ''
         install -m 0755 -d /var/log/glusterfs
+      ''
+      # The copying of hooks is due to upstream bug https://bugzilla.redhat.com/show_bug.cgi?id=1452761
+      + ''
         mkdir -p /var/lib/glusterd/hooks/
         ${rsync}/bin/rsync -a ${glusterfs}/var/lib/glusterd/hooks/ /var/lib/glusterd/hooks/
+      ''
+      # `glusterfind` needs dirs that upstream installs at `make install` phase
+      # https://github.com/gluster/glusterfs/blob/v3.10.2/tools/glusterfind/Makefile.am#L16-L17
+      + ''
+        mkdir -p /var/lib/glusterd/glusterfind/.keys
+        mkdir -p /var/lib/glusterd/hooks/1/delete/post/
       '';
 
       serviceConfig = {