Issue here is, socket of the killed connection (using KILL
statement) is not closed. Because of this assert condition
to check if socket buffer is empty, failed.

When thread is in the kill immune mode, kill is not executed
immediately. kill state is saved and it is applied while exiting
from the kill immune mode. If the operation is KILL_CONNECTION
then thread socket connection should be closed but while exiting
kill immune mode socket was not getting closed. Hence write to
socket after this step as causing client side assertion.

To fix this issue, code is modified to close socket connection
for KILL_CONNECTION operation even while exiting from the
kill immune mode.

Change-Id: I96a9543c9173fd5840ce25e7e6c45e060a680802