Attempt to fix "run --once" test by giving Mongo a chance to exit.
Attempt to fix "run --once" test by giving Mongo a chance to exit.

This test has been failing intermittently on Circle CI.

Hansoft/meteor,mjmasn/meteor,Hansoft/meteor,mjmasn/meteor,mjmasn/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,Hansoft/meteor,mjmasn/meteor,mjmasn/meteor,mjmasn/meteor,mjmasn/meteor