LU-11591 llog: remove partial_chunk variable

LU-11591 llog: remove partial_chunk variable

This variable is set but never used, so remove it.

Test-Parameters: trivial
Fixes: ec4194e4e78c ("LU-11591 llog: add synchronization for the last record")
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I59ec75ba66a3ca37990d3ffec1d1b8f80350ae52
Reviewed-on: https://review.whamcloud.com/37830
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexander Boyko <c17825@cray.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>