Fix bios name warning

@johnsimons, I see your commit "Fixed NETBIOS name warning." (commit b8f58f794f28355c70733fab4ae08bc72614e3c7) from a week ago.

As per the forum discussion, 15 characters _is_ actually ok.  Only reason I care is because I keep seeing erroneous warnings in the logs and that's just unnecessary noise.

relevant forum post: http://tech.groups.yahoo.com/group/nservicebus/message/18178
relevant ms reference: http://support.microsoft.com/kb/163409
and fwiw, I've had NSB running fine with DTC and my machine name is exactly 15 char long.  :)

cheers
justin