MINOR: ssl: support strict-sni in ssl-default-bind-options

MINOR: ssl: support strict-sni in ssl-default-bind-options

Several users already reported that it would be nice to support
strict-sni in ssl-default-bind-options. However, in order to support
it, we also need an option to disable it.

This patch moves the setting of the option from the strict_sni field
to a flag in the ssl_options field so that it can be inherited from
the default bind options, and adds a new "no-strict-sni" directive to
allow to disable it on a specific "bind" line.

The test file "del_ssl_crt-list.vtc" which already tests both options
was updated to make use of the default option and the no- variant to
confirm everything continues to work.