nixos: set all package options to have type package

nixos/modules/services/databases/firebird.nix

@@ -49,6 +49,7 @@ in
 
       package = mkOption {
         default = pkgs.firebirdSuper;
+        type = types.package;
         /*
           Example: <code>package = pkgs.firebirdSuper.override { icu =
             pkgs.icu; };</code> which is not recommended for compatibility

nixos/modules/services/databases/mongodb.nix

@@ -39,6 +39,7 @@ in
 
       package = mkOption {
         default = pkgs.mongodb;
+        type = types.package;
         description = "
           Which MongoDB derivation to use.
         ";

nixos/modules/services/databases/postgresql.nix

@@ -55,7 +55,7 @@ in
       };
 
       package = mkOption {
-        type = types.path;
+        type = types.package;
         example = literalExample "pkgs.postgresql92";
         description = ''
           PostgreSQL package to use.

nixos/modules/services/databases/redis.nix

@@ -45,6 +45,7 @@ in
       package = mkOption {
         default = pkgs.redis;
         description = "Which Redis derivation to use.";
+        type = types.package;
       };
 
       user = mkOption {