BUG/MINOR: tcpcheck: Don't forget to reset tcp-check flags on new kind of check

BUG/MINOR: tcpcheck: Don't forget to reset tcp-check flags on new kind of check

When a new kind of check is found during the parsing of a proxy section (via
an option directive), we must reset tcpcheck flags for this proxy. It is
mandatory to not inherit some flags from a previously declared check (for
instance in the default section).

This patch must be backported as far as 2.2.

(cherry picked from commit 1faf18ae3976cddfb17afa95ea447205330c821e)
Signed-off-by: William Lallemand <wlallemand@haproxy.org>