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.
diff --git a/src/tree_schema.c b/src/tree_schema.c
index 702563a..86de5c4 100644
--- a/src/tree_schema.c
+++ b/src/tree_schema.c
@@ -1634,7 +1634,7 @@
 }
 
 API LY_ERR
-lys_parse(struct ly_ctx *ctx, struct ly_in *in, LYS_INFORMAT format, const char **features, const struct lys_module **module)
+lys_parse(struct ly_ctx *ctx, struct ly_in *in, LYS_INFORMAT format, const char **features, struct lys_module **module)
 {
     LY_ERR ret = LY_SUCCESS;
     struct lys_module *mod;
@@ -1678,7 +1678,7 @@
 }
 
 API LY_ERR
-lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, const struct lys_module **module)
+lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, struct lys_module **module)
 {
     LY_ERR ret;
     struct ly_in *in = NULL;
@@ -1694,7 +1694,7 @@
 }
 
 API LY_ERR
-lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format, const struct lys_module **module)
+lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format, struct lys_module **module)
 {
     LY_ERR ret;
     struct ly_in *in = NULL;
@@ -1710,7 +1710,7 @@
 }
 
 API LY_ERR
-lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format, const struct lys_module **module)
+lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format, struct lys_module **module)
 {
     LY_ERR ret;
     struct ly_in *in = NULL;