Fix a couple of warnings in test suite

Fix a couple of warnings in test suite

src/utils_vl_lookup_test.c: In function ‘checked_lookup_add’:
src/utils_vl_lookup_test.c:91:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(ident.host, host, sizeof(ident.host));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:92:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(ident.plugin, plugin, sizeof(ident.plugin));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:93:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(ident.plugin_instance, plugin_instance,
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           sizeof(ident.plugin_instance));
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:95:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(ident.type, type, sizeof(ident.type));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:96:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(ident.type_instance, type_instance, sizeof(ident.type_instance));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c: In function ‘checked_lookup_search’:
src/utils_vl_lookup_test.c:113:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(vl.host, host, sizeof(vl.host));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:114:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(vl.plugin, plugin, sizeof(vl.plugin));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:115:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(vl.plugin_instance, plugin_instance, sizeof(vl.plugin_instance));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:116:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(vl.type, type, sizeof(vl.type));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/utils_vl_lookup_test.c:117:3: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation]
   strncpy(vl.type_instance, type_instance, sizeof(vl.type_instance));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CCLD     test_utils_vl_lookup