nixos/nextcloud: don't make phpPackages configurable

It needs to match the version in phpfm which is hard coded.
So there is no point in being able to change it.

nixos/modules/services/web-apps/nextcloud.nix

@@ -5,15 +5,18 @@ with lib;
 let
   cfg = config.services.nextcloud;
 
+  phpPackage = pkgs.php73;
+  phpPackages = pkgs.php73Packages;
+
   toKeyValue = generators.toKeyValue {
     mkKeyValue = generators.mkKeyValueDefault {} " = ";
   };
 
   phpOptionsExtensions = ''
-    ${optionalString cfg.caching.apcu "extension=${cfg.phpPackages.apcu}/lib/php/extensions/apcu.so"}
-    ${optionalString cfg.caching.redis "extension=${cfg.phpPackages.redis}/lib/php/extensions/redis.so"}
-    ${optionalString cfg.caching.memcached "extension=${cfg.phpPackages.memcached}/lib/php/extensions/memcached.so"}
-    extension=${cfg.phpPackages.imagick}/lib/php/extensions/imagick.so
+    ${optionalString cfg.caching.apcu "extension=${phpPackages.apcu}/lib/php/extensions/apcu.so"}
+    ${optionalString cfg.caching.redis "extension=${phpPackages.redis}/lib/php/extensions/redis.so"}
+    ${optionalString cfg.caching.memcached "extension=${phpPackages.memcached}/lib/php/extensions/memcached.so"}
+    extension=${phpPackages.imagick}/lib/php/extensions/imagick.so
     zend_extension = opcache.so
     opcache.enable = 1
   '';
@@ -95,18 +98,6 @@ in {
       '';
     };
 
-    phpPackages = mkOption {
-      type = types.attrs;
-      default = pkgs.php73Packages;
-      defaultText = "pkgs.php73Packages";
-      description = ''
-        Overridable attribute of the PHP packages set to use.  If any caching
-        module is enabled, it will be taken from here.  Therefore it should
-        match the version of PHP given to
-        <literal>services.phpfpm.phpPackage</literal>.
-      '';
-    };
-
     phpOptions = mkOption {
       type = types.attrsOf types.str;
       default = {
@@ -367,7 +358,7 @@ in {
                 phpOptions)));
         in {
           phpOptions = phpOptionsExtensions;
-          phpPackage = pkgs.php73;
+          phpPackage = phpPackage;
           listen = "/run/phpfpm/nextcloud";
           extraConfig = ''
             listen.owner = nginx