BUG/MINOR: http: usual deinit stuff in last commit

We need to initialize the rdr_fmt list inconditionally. Using only
a redirect rule without an http-redirect may cause a crash during
deinit because of the list iterating from null.
BUILD: log: silent a warning about isblank() with latest patches

Recent commit 06d97f9 (MEDIUM: log-format: relax parsing of '%' followed
by unsupported characters) caused the following warning on some compilers
since isblank is not always present :

  src/log.c: In function 'parse_logformat_string':
  src/log.c:453: warning: implicit declaration of function 'isblank'

As usual, replace it with the two values (space and tab).
BUG/MEDIUM: checks: fix health check regression causing them to depend on declaration order

Since commit 4a74143 (MEDIUM: Paramatise functions over the check of a
server), the check type is inherited from the current proxy's check type
at the moment where the server is declared instead of when reviewing
server configs. This causes an issue where a health check is disabled
when the server is declared before the checks. In fact the server will
inherit the last known check type declared before the "server" line :

  backend foo
        # this server is not checked at all
        server s1 1.1.1.1:80 check
        option tcpchk
        # this server is tcp-checked :
        server s2 1.1.1.2:80 check
        option httpchk
        # this server is http-checked :
        server s3 1.1.1.3:80 check

The fix consists in assigning the check type during the config review
phase where the config is stable. No backport is nedeed.