[Samba] mount.cifs drops connection to windows server on group policy refresh

[Freeman, Deric]

Client is mount.cifs version: 6.2 on Red Hat Enterprise Linux Server release 7.1 (Maipo)

Connecting to a Windows 2008 R2 File Server.

The client will maintain a connection to the server until a group policy refresh is triggered on the server.  Anytime a group policy refresh occurs on the server, the client is disconnected.

If we don't explicitly specify vers= option it will reconnect after ~15 minutes.

If we set vers=2.1 it will "Input/output error" if attempting to ls the mount point; it will not reconnect without explicitly umount first and mount -a