LU-11397 idl: remove obsolete RPC flags

LU-11397 idl: remove obsolete RPC flags

Remove RPC flags that are no longer in use:
- OBD_MD_FLQOS		has never been used in master branch
- OBD_MD_FLEPOCH	unused since v2_7_50_0-38-gd5d5b349f2
- OBD_MD_REINT		unused since before 1.6
- OBD_MD_FLMDSCAPA	unused since v2_7_55_0-15-g353ef58b1d
- OBD_MD_FLOSSCAPA	unused since v2_7_55_0-15-g353ef58b1d

Rename OBD_MD_FLGENER to OBD_MD_FLPARENT to more accurately describe
that this flag is only used to mark the parent FID in the OST obdo.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I7ef8ee5a403a7f4d0184bb279198d93e1198e9de
Reviewed-on: https://review.whamcloud.com/33202
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>