LU-14119 mdc: set fid2path RPC interruptible

LU-14119 mdc: set fid2path RPC interruptible

Sometimes OI scrub can't fix the inconsistency in FID and name, and
server will return -EINPROGRESS for fid2path request. Upon such
failure, client will keep resending the request. Set such request
to be interruptible to avoid deadlock.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I82192cb8a8256064ca632cabfe5581b12e86423b
Reviewed-on: https://review.whamcloud.com/41219
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>