Don't use deprected "1" value to cURL CURLOPT_SSL_VERIFYHOST

Summary: Fixes T2962. That task discusses this issue.

Test Plan: Read php-curl documentation to verify this change makes sense. Sent an email with SES.

Reviewers: btrahan, garoevans

Reviewed By: garoevans

CC: aran

Maniphest Tasks: T2962

Differential Revision: https://secure.phabricator.com/D5669