BG-8135: Override sjcl initialization vector
BG-8135: Override sjcl initialization vector

Summary: Signed-off-by: Tyler Levine <tyler@bitgo.com>

Reviewers: bigly, leo, benchan, zacleids

Reviewed By: zacleids

Subscribers: tyler

Differential Revision: https://phabricator.bitgo.com/D10071

BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS