BUG/MINOR: ssl/ckch: always ha_freearray() the previous entry during parsing

BUG/MINOR: ssl/ckch: always ha_freearray() the previous entry during parsing

The ckch_conf_parse() function is the generic function which parses
crt-store keywords from the crt-store section, and also from a
crt-list.

When having multiple time the same keyword, a leak of the previous
value happens. This patch ensure that the previous value is always
freed before overwriting it.

This is the same problem as the previous "BUG/MINOR: ssl/ckch: always
free() the previous entry during parsing" patch, however this one
applies on PARSE_TYPE_ARRAY_SUBSTR.

No backport needed.