*) mod_md: v2.4.0 with improvements and bugfixes

  *) mod_md: v2.4.0 with improvements and bugfixes
     - MDPrivateKeys allows the specification of several types. Beside "RSA" plus
     optional key lengths elliptic curves can be configured. This means you can
     have multiple certificates for a Managed Domain with different key types.
     With ```MDPrivateKeys secp384r1 rsa2048``` you get one ECDSA  and one RSA
     certificate and all modern client will use the shorter ECDSA, while older
     client will get the RSA certificate.
     Many thanks to @tlhackque who pushed and helped on this.
     - Support added for MDomains consisting of a wildcard. Configuring
     ```MDomain *.host.net``` will match all virtual hosts matching that pattern
     and obtain one certificate for it (assuming you have 'dns-01' challenge
     support configured). Addresses #239.
     - Removed support for ACMEv1 servers. The only known installation used to
     be Let's Encrypt which has disabled that version more than a year ago for
     new accounts.
     - Andreas Ulm (<https://github.com/root360-AndreasUlm>) implemented the
     ```renewing``` call to ```MDMessageCmd``` that can deny a certificate
     renewal attempt. This is useful in clustered installations, as
     discussed in #233).
     - New event ```challenge-setup:<type>:<domain>```, triggered when the
     challenge data for a domain has been created. This is invoked before the
     ACME server is told to check for it. The type is one of the ACME challenge
     types. This is invoked for every DNS name in a MDomain.
     - The max delay for retries has been raised to daily (this is like all
     retries jittered somewhat to avoid repeats at fixed time of day).
     - Certain error codes reported by the ACME server that indicate a problem
     with the configured data now immediately switch to daily retries. For
     example: if the ACME server rejects a contact email or a domain name,
     frequent retries will most likely not solve the problem. But daily retries
     still make sense as there might be an error at the server and un-supervised
     certificate renewal is the goal. Refs #222.
     - Test case and work around for domain names > 64 octets. Fixes #227.
     When the first DNS name of an MD is longer than 63 octets, the certificate
     request will not contain a CN field, but leave it up to the CA to choose one.
     Currently, Lets Encrypt looks for a shorter name in the SAN list given and
     fails the request if none is found. But it is really up to the CA (and what
     browsers/libs accept here) and may change over the years. That is why
     the decision is best made at the CA.
     - Retry delays now have a random +/-[0-50]% modification applied to let
     retries from several servers spread out more, should they have been
     restarted at the same time of day.
     - Fixed several places where the 'badNonce' return code from an ACME server
     was not handled correctly. The test server 'pebble' simulates this behaviour
     by default and helps nicely in verifying this behaviour. Thanks, pebble!
     - Set the default `MDActivationDelay` to 0. This was confusing to users that
     new certificates were deemed not usably before a day of delay. When clocks are
     correct, using a new certificate right away should not pose a problem.
     - When handling ACME authorization resources, the module no longer requires
     the server to return a "Location" header, as was necessary in ACMEv1.
     Fixes #216.
     - Fixed a theoretical uninitialized read when testing for JSON error responses
     from the ACME CA. Reported at <https://bz.apache.org/bugzilla/show_bug.cgi?id=64297>.
     - ACME problem reports from CAs that include parameters in the Content-Type
     header are handled correctly. (Previously, the problem text would not be
     reported and retries could exist CA limits.)
     - Account Update transactions to V2 CAs now use the correct POST-AS-GET method.
     Previously, an empty JSON object was sent - which apparently LE accepted,
     but others reject.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1887337 13f79535-47bb-0310-9956-ffa450edef68