af-packet: fix problem introduced in recent commit

Logic of patch 98e4a14f6d59fe8928fd6e2af3d9c3e8b42d00bf was correct
but implementation is wrong because TP_STATUS_KERNEL is equal to
zero and thus can not be evaluated in a binary operation. This patch
updates the logic by doing two tests.

Reported-by: Alessandro Guido
Bug 980: fix HTTP memory cleanup at shutdown

Buffers in per thread HTTP header, client body and server body storage
would be freed based on the usage indicator instead of the size
indicator.

As the usage indicator (e.g. hsbd_buffers_list_len) could be reset
while leaving the memory untouched for later reuse, the free function
would not iterate over all memory blocks.

Removed DrMemory suppressions as well.

Bug #980.