Bump `mongo` version to 1.4.6 prior to publishing.
Bump `mongo` version to 1.4.6 prior to publishing.

This includes the changes for meteor/meteor#9739 for testing, but we will
immediately publish 1.4.7 with this commit reverted.

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