LU-8998 tools: support negative flags

LU-8998 tools: support negative flags

- Make 'lfs setstripe --component-flags' support negative flags
  "^init".
- Change llapi_layout_file_comp_del() to accept both 'id' and
  'flags', 'id' must be real ID, 'flags' can be negative flags.
- Fix swab defect in lod_declare_layout_del().
- Update man pages and test scripts accordingly.

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: I9b66492133f56eabc928dbbb41bb8eb5627be095
Reviewed-on: https://review.whamcloud.com/26490
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>