Fixes several bugs for libhns:
libhns: Fix memory leakage when DCA is enabled
libhns: Fix the exception branch of wr_start() is not locked
Signed-off-by: Xinghai Cen <cenxinghai@h-partners.com>
(cherry picked from commit 62a65084134c9b3be711dc25ef02b900a7b9a345)
