nacm BUGFIX extension records

... can only have the same addresses thanks to translator optimization.
So it cannot be relied upon.
diff --git a/src/plugins_exts/nacm.c b/src/plugins_exts/nacm.c
index 5ab8daa..df49721 100644
--- a/src/plugins_exts/nacm.c
+++ b/src/plugins_exts/nacm.c
@@ -101,7 +101,7 @@
 
     /* check for duplication */
     LY_ARRAY_FOR(parent->exts, u) {
-        if ((&parent->exts[u] != ext) && parent->exts[u].record && (parent->exts[u].record->plugin.id == ext->record->plugin.id)) {
+        if ((&parent->exts[u] != ext) && parent->exts[u].record && !strcmp(parent->exts[u].record->plugin.id, ext->record->plugin.id)) {
             /* duplication of a NACM extension on a single node
              * We check for all NACM plugins since we want to catch even the situation that there is default-deny-all
              * AND default-deny-write */