36090b7161 removed use_secure_element from httpd_ssl_config and from
HTTPD_SSL_CONFIG_DEFAULT(). 8fe74703bc then restored the member to the
struct to keep source compatibility, but did not restore it to the macro,
so HTTPD_SSL_CONFIG_DEFAULT() no longer initializes every member of the
struct it is documented to initialize.
C tolerates the gap in designated initializers, but C++ diagnoses it as
-Wmissing-field-initializers, which is fatal for applications built with
-Werror.
