BG-8638: Don't update npm before installing on travis
BG-8638: Don't update npm before installing on travis

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

Reviewers: bigly, danny, zacleids, leo

Reviewed By: leo

Subscribers: tyler

Differential Revision: https://phabricator.bitgo.com/D10320

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