varlink: move definition of varlink_hash_ops into common code

This is truly useful whenever we have to deal with multiple varlink
connections.

src/import/importd.c

@@ -130,8 +130,6 @@ static const char* const transfer_type_table[_TRANSFER_TYPE_MAX] = {
 
 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(transfer_type, TransferType);
 
-DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(varlink_hash_ops, void, trivial_hash_func, trivial_compare_func, sd_varlink, sd_varlink_unref);
-
 static Transfer *transfer_unref(Transfer *t) {
         if (!t)
                 return NULL;

src/libsystemd/sd-varlink/varlink-util.c

@@ -203,3 +203,11 @@ int varlink_check_privileged_peer(sd_varlink *vl) {
 
         return 0;
 }
+
+DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
+                varlink_hash_ops,
+                void,
+                trivial_hash_func,
+                trivial_compare_func,
+                sd_varlink,
+                sd_varlink_unref);

src/libsystemd/sd-varlink/varlink-util.h

@@ -27,3 +27,5 @@ int varlink_server_new(
                 void *userdata);
 
 int varlink_check_privileged_peer(sd_varlink *vl);
+
+extern const struct hash_ops varlink_hash_ops;