Add option to ignore server provided failover partner

[David-Engel]

Is your feature request related to a problem? Please describe.

Due to unique networking configurations for some clients of an application, the failover partner information defined on the server can't be reached over the network without using a custom server name for the failover partner for those clients.

Describe the solution you'd like

Customers would like to be able to specify a failover partner on the client that will not get overridden by the failover partner information provided by the server. Ideally, this would be a connection string option like ignoreServerFailoverPartner=true.

Describe alternatives you've considered

Disabling the failover partner information sent by the server via a server-side trace flag. However, this is not an ideal solution.

[edwardneal]

I've had this problem before, and something to work around it would be useful. The situation I encountered it in related primarily to multiple domains. The SQL Server instances would be in the resources.contoso.com domain, and mirroring was configured to use single-label names. This caused a problem when the clients are in the ad.contoso.com domain - the connection string's server name and failover partner would use FQDNs, but the failover partner was overwritten with a single-label name (which would never resolve.)