Made SSL validation in Curl HTTP requests the default.

Changed the default value for CURLOPT_SSL_VERIFYHOST
to 2 rather than true. This makes sure that hostname
validation occurs.

Change-Id: Ia6535f1090627ef2def360bda37c22bff10c7f31
(cherry picked from commit 5c8d6fa60f521073136012f67e66bdb72010e720)