Revert "Re-enable SSL certificate verification"

SNI issues are not entirely transient. Until long-term fix is in
place, bring back the disabling of SSL certificates. Original
caution still goes without saying: this must be re-enabled before
production use.

This reverts commit 7464c8036d9acb4557250139e1d25520fc4a6ecf.

Signed-off-by: Jeff Godin <jgodin@tadl.org>