Set Raven DB name when conn string doesn't have it. Closes #1064

If the connection string was specified but with a server url only and
no database was set in the string then it should set the database to
the EndPointName.

Relates to #1000

Conflicts:
	src/NServiceBus.Core.Tests/Persistence/RavenDB/When_configuring_persistence_to_use_a_raven_server_instance_using_a_connection_string.cs
	src/NServiceBus.Core/ConfigureRavenPersistence.cs