BUG/MINOR: server: Init params before parsing a new server-state line

BUG/MINOR: server: Init params before parsing a new server-state line

Same static arrays of parameters are used to parse all server-state
lines. Thus it is important to reinit them to be sure to not get params from
the previous line, eventually from the previous loaded file.

This patch should be backported to all stable branches. However, in 2.0 and
prior, the parsing of server-state lines are inlined in apply_server_state()
function. Thus the patch will have to be adapted on these versions.

(cherry picked from commit 06cd2569786d31ebb15832cb1053be9aaaadc3f7)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>