LU-11075 ldlm: correct logic in ldlm_prepare_lru_list()

LU-11075 ldlm: correct logic in ldlm_prepare_lru_list()

In ldlm_prepare_lru_list() fix an (x != a || x != b) type error and
correct a use after free.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I4e34e531260295805c4461e7d8d98675400f1148
Reviewed-on: https://review.whamcloud.com/32660
Tested-by: Jenkins
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>