BUG/MINOR: stats: http-request rules still don't cope with stats

Since commit 20b0de5, we also had another remaining issue : an
"http-request allow" rule would prevent a stats rule from being
processed.
BUG/MINOR: http: http-request add-header emits a corrupted header

David BERARD reported that http-request add-header passes a \0 along
with the header field, which of course is not appropriate. This is
caused by build_logline() which sometimes returns the size with the
trailing zero and sometimes can return an empty string. Let's fix
this function instead of fixing the places where it's used.
BUG/MEDIUM: stats: disable request analyser when processing POST or HEAD

After the response headers are sent and the request processing is done,
the buffers are wiped out and the stream interface is closed. We must
then disable the request analysers, otherwise some processing will
happen on a closed stream interface and empty buffers which do not
match, causing all sort of crashes. This issue was introduced with
recent work on the stats, and was reported by Seri.
BUG/MINOR: log: make log-format, unique-id-format and add-header more independant

It happens that all of them call parse_logformat_line() which sets
proxy->to_log with a number of flags affecting the line format for
all three users. For example, having a unique-id specified disables
the default log-format since fe->to_log is tested when the session
is established.

Similarly, having "option logasap" will cause "+" to be inserted in
unique-id or headers referencing some of the fields depending on
LW_BYTES.

This patch first removes most of the dependency on fe->to_log whenever
possible. The first possible cleanup is to stop checking fe->to_log
for being null, considering that it always contains at least LW_INIT
when any such usage is made of the log-format!

Also, some checks are wrong. s->logs.logwait cannot be nulled by
"logwait &= ~LW_*" since LW_INIT is always there. This results in
getting the wrong log at the end of a request or session when a
unique-id or add-header is set, because logwait is still not null
but the log-format is not checked.

Further cleanups are required. Most LW_* flags should be removed or at
least replaced with what they really mean (eg: depend on client-side
connection, depend on server-side connection, etc...) and this should
only affect logging, not other mechanisms.

This patch fixes the default log-format and tries to limit interferences
between the log formats, but does not pretend to do more for the moment,
since it's the most visible breakage.
BUILD: log: unused variable svid

This results from previous fix.
CLEANUP: http: rename the misleading http_check_access_rule

Several bugs were introduced recently due to a misunderstanding of how
this function works and what it was supposed to do. Since it's supposed
to only return the pointer to a rule which aborts further processing of
the request, let's rename it to avoid further issues.

The function was also slightly cleaned up without any functional change.
MINOR: http: move redirect rule processing to its own function

We now have http_apply_redirect_rule() which does all the redirect-specific
job instead of having this inside http_process_req_common().

Also one of the benefit gained from uniformizing this code is that both
keep-alive and close response do emit the PR-- flags. The fix for the
flags could probably be backported to 1.4 though it's very minor.

The previous function http_perform_redirect() was becoming confusing
so it was renamed http_perform_server_redirect() since it only applies
to server-based redirection.
REORG: config: move the http redirect rule parser to proto_http.c

We'll have to use this elsewhere soon, let's move it to the proper
place.
MEDIUM: http: add support for "http-request redirect" rules

These are exactly the same as the classic redirect rules except
that they can be interleaved with other http-request rules for
more flexibility.

The redirect parser should probably be changed to stop at the condition
so that the caller puts its own condition pointer. At the moment, the
redirect rule and condition are parsed at once by build_redirect_rule()
and the condition is assigned to the http_req_rule.
MEDIUM: http: add support for "http-request tarpit" rule

The "reqtarpit" rule is not very handy to use. Now that we have more
flexibility with "http-request", let's finally make the tarpit rules
usable there.

There are still semantical differences between apply_filters_to_request()
and http_req_get_intercept_rule() because the former updates the counters
while the latter does not. So we currently have almost similar code leafs
for similar conditions, but this should be cleaned up later.
MINOR: ssl: Setting global tune.ssl.cachesize value to 0 disables SSL session cache.
[RELEASE] Released version 1.5-dev17

Released version 1.5-dev17 with the following main changes :
    - MINOR: ssl: Setting global tune.ssl.cachesize value to 0 disables SSL session cache.
    - BUG/MEDIUM: stats: fix stats page regression introduced by commit 20b0de5
    - BUG/MINOR: stats: last fix was still wrong
    - BUG/MINOR: stats: http-request rules still don't cope with stats
    - BUG/MINOR: http: http-request add-header emits a corrupted header
    - BUG/MEDIUM: stats: disable request analyser when processing POST or HEAD
    - BUG/MINOR: log: make log-format, unique-id-format and add-header more independant
    - BUILD: log: unused variable svid
    - CLEANUP: http: rename the misleading http_check_access_rule
    - MINOR: http: move redirect rule processing to its own function
    - REORG: config: move the http redirect rule parser to proto_http.c
    - MEDIUM: http: add support for "http-request redirect" rules
    - MEDIUM: http: add support for "http-request tarpit" rule
Merge remote-tracking branch 'upstream/master'