Fix rare "error 2062" failure in various tests

Summary:
Occasionally, wait_until_connected_again will fail with error 2062,
when its supposed to continue to retry.

This adds that error to its list of acceptable errors while retrying.

Note: If it never successfully reconnects, the test will still fail,
so this does not hide any actual errors.  It just removes some false
test failures.

Test Plan:
Jenkins

The stress tests suite found this bug, but the problem is not
specific to those tests.

Reviewers: pivanof, darnaut, inaam-rana, jeremycole

Reviewed By: jeremycole

Subscribers: CalvinSun, jtolmer

Differential Revision: https://reviews.facebook.net/D23607