XROOTD: Drop the xcastor2.fs configuration option which is not used.

        Refactor some variable names to follow the naming conventions.
        Properly use the Eroute object before the logging is configured.
        Fix the fsctl function which now (XrootD 4.0) uses as command a combination of flags, therefore
	comparing with SFS_FSCTL_LOCATE is not enough, we need to do a bitwise "and" (&).