Removing the deprecated __xray_log_init API from XRay FDR logging implementation

I’d like to remove __xray_log_init function together with FDRLoggingOptions and BasicLoggingOptions structs from the XRay FDR logging interface.

These functions have been marked as deprecated since May 4, 2018. Now that 7.0 has been branched, I think it should be safe to remove them and it’d make further refactoring that I’m currently working on much easier, but I want to check that all users have already moved away from this API and won’t be broken by this change? If nobody raises any objections, I’d send out a change to remove this API.

+1 from me. Thanks Petr!