nixos/ipfs: Improve behavior of localDiscovery option

It is no longer required to change the config your ipfs repo manually if you change
localDiscovery option in nixos configuration after ipfs repository initialization.

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

@@ -189,9 +189,7 @@ in {
       localDiscovery = mkOption {
         type = types.bool;
         description = ''Whether to enable local discovery for the ipfs daemon.
-          This will prevent ipfs to scan ports on your local network. Some hosting services will ban you if you do.
-
-          This option only has an effect before you initialized ipfs your machine.
+          This will allow ipfs to scan ports on your local network. Some hosting services will ban you if you do this.
         '';
         default = true;
       };
@@ -244,6 +242,11 @@ in {
         if [[ ! -f ${cfg.dataDir}/config ]]; then
           ipfs init ${optionalString cfg.emptyRepo "-e"} \
             ${optionalString (! cfg.localDiscovery) "--profile=server"}
+        else
+          ${if cfg.localDiscovery
+            then "ipfs config profile apply local-discovery"
+            else "ipfs config profile apply server"
+          }
         fi
       '';