Fix missing return value checks in multi_process_float()

Fix missing return value checks in multi_process_float()

Fix the missing return value checks on hash_remove() and hash_add() by
replacing the calls with an single hash_add() call with the replace
parameters set to true so that is can't fail.  Then just ASSERT() that
this is indeed the case.

This also replaces the other add/remove combinations with a single
add-replace, because that should be slightly faster (and this is in the
'hot path').

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: David Sommerseth <davids@openvpn.net>
Message-Id: <1478635663-5837-1-git-send-email-steffan@karger.me>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg12968.html
Signed-off-by: David Sommerseth <davids@openvpn.net>