K 10 svn:author V 3 mav K 8 svn:date V 27 2019-03-11T01:44:37.616576Z K 7 svn:log V 423 MFC r344489: Free some space in struct ctl_io_hdr for better use. - Collapse original_sc and serializing_sc fields into one, since they are never used simultanously, we have only one local I/O and one remote. - Move remote_sglist and local_sglist fields into CTL_PRIV_BACKEND, since they are used only on Originating SC in XFER mode, where requests don't ever reach backends, so we can reuse backend's private storage. END