schema CHANGE avoid unnecessary check

When using extension's name which was already checked by parser for its
syntax correctness, it is not necessary to check its correctness again
and just trust that the name can be correctly parsed for further
processing.

Avoids compiler's warning in RELEASE mode about not using the set
variable.
diff --git a/src/tree_schema_helpers.c b/src/tree_schema_helpers.c
index a709d88..526ee61 100644
--- a/src/tree_schema_helpers.c
+++ b/src/tree_schema_helpers.c
@@ -1822,7 +1822,6 @@
 lysp_ext_find_definition(const struct ly_ctx *ctx, const struct lysp_ext_instance *ext, const struct lys_module **ext_mod,
         struct lysp_ext **ext_def)
 {
-    LY_ERR r;
     const char *tmp, *name, *prefix;
     size_t pref_len, name_len;
     LY_ARRAY_COUNT_TYPE v;
@@ -1833,11 +1832,9 @@
         *ext_mod = NULL;
     }
 
-    /* parse the prefix */
+    /* parse the prefix, the nodeid was previously already parsed and checked */
     tmp = ext->name;
-    r = ly_parse_nodeid(&tmp, &prefix, &pref_len, &name, &name_len);
-    /* it was parsed already */
-    assert(!r && !tmp[0]);
+    ly_parse_nodeid(&tmp, &prefix, &pref_len, &name, &name_len);
 
     /* get module where the extension definition should be placed */
     mod = ly_resolve_prefix(ctx, prefix, pref_len, ext->format, ext->prefix_data);