meson option: make the insecure-disable-auth macro more accurate

The "auth" term is overloaded in meson option and macros. This commit
changes the macro from BMCWEB_INSECURE_DISABLE_AUTHENTICATION to
BMCWEB_INSECURE_DISABLE_AUTHX, given that if "insecure-disable-auth"
is enabled, both authentication and authorization are disabled.

Tested:
1. set 'insecure-disable-auth=enabled', no authz nor authn is performed,
no crash on AccountService as well.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: Iddca1f866d16346bcc2017338fa6f077cb89cef9
diff --git a/meson.build b/meson.build
index 33daf54..8724c62 100644
--- a/meson.build
+++ b/meson.build
@@ -65,7 +65,7 @@
   'google-api'                                  : '-DBMCWEB_ENABLE_GOOGLE_API',
   'host-serial-socket'                          : '-DBMCWEB_ENABLE_HOST_SERIAL_WEBSOCKET',
   'ibm-management-console'                      : '-DBMCWEB_ENABLE_IBM_MANAGEMENT_CONSOLE',
-  'insecure-disable-auth'                       : '-DBMCWEB_INSECURE_DISABLE_AUTHENTICATION',
+  'insecure-disable-auth'                       : '-DBMCWEB_INSECURE_DISABLE_AUTHX',
   'insecure-disable-csrf'                       : '-DBMCWEB_INSECURE_DISABLE_CSRF_PREVENTION',
   'insecure-disable-ssl'                        : '-DBMCWEB_INSECURE_DISABLE_SSL',
   'insecure-push-style-notification'            : '-DBMCWEB_INSECURE_ENABLE_HTTP_PUSH_STYLE_EVENTING',