log BUGFIX generate libyang path

... because it is retrieved by other
functions.
Fixes #207
diff --git a/src/messages_server.c b/src/messages_server.c
index 26ce1b8..98d917a 100644
--- a/src/messages_server.c
+++ b/src/messages_server.c
@@ -470,7 +470,7 @@
             break;
         case LYVE_INELEM:
             str = ly_errpath(ctx);
-            if (!strcmp(str, "/")) {
+            if (!str || !strcmp(str, "/")) {
                 e = nc_err(NC_ERR_OP_NOT_SUPPORTED, NC_ERR_TYPE_APP);
                 /* keep default message */
                 return e;