parser schema CHANGE always return non-const modules

Refs #1645
diff --git a/src/parser_schema.h b/src/parser_schema.h
index ecb3851..bddb300 100644
--- a/src/parser_schema.h
+++ b/src/parser_schema.h
@@ -103,7 +103,7 @@
  * @return LY_ERR value.
  */
 LY_ERR lys_parse(struct ly_ctx *ctx, struct ly_in *in, LYS_INFORMAT format, const char **features,
-        const struct lys_module **module);
+        struct lys_module **module);
 
 /**
  * @brief Load a schema into the specified context.
@@ -117,7 +117,7 @@
  * @param[out] module Optional parsed module.
  * @return LY_ERR value.
  */
-LY_ERR lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, const struct lys_module **module);
+LY_ERR lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, struct lys_module **module);
 
 /**
  * @brief Read a schema from file descriptor into the specified context.
@@ -134,7 +134,7 @@
  * @param[out] module Optional parsed module.
  * @return LY_ERR value.
  */
-LY_ERR lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format, const struct lys_module **module);
+LY_ERR lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format, struct lys_module **module);
 
 /**
  * @brief Load a schema into the specified context from a file.
@@ -148,7 +148,7 @@
  * @param[out] module Optional parsed module.
  * @return LY_ERR value.
  */
-LY_ERR lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format, const struct lys_module **module);
+LY_ERR lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format, struct lys_module **module);
 
 /**
  * @brief Search for the schema file in the specified searchpaths.