Add OBD_CONNECT2_FIDMAP connect flag, which indicates whether client
supports FID mapping.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I165598e7d19878d1d3dcfa8c6f8fcc3cc233e4c9
Reviewed-on: https://review.whamcloud.com/38232


Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>