Sync tcf_action_init and tca_action_gd. Rename a few variables
to make the code more easily understandable and rename the
rtattr_failure/nlmsg_failure labels. These are usually called
from the netlink macros, it is misleading to use them in a
larger function without actually using netlink macros.

Multi action orders were processed differently before,
tcf_action_init skipped empty ones while tca_action_gd stopped
at the first empty one. This patch makes both stop at the first
empty one.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>