OTP-12845

* bruce/change-license:
  fix errors caused by changed line numbers
  Change license text to APLv2

* anders/diameter/sctp/OTP-12768:
  Fix connection timeouts in test transports
  Fix start order of alternate transports
  Log discarded answers
  Ensure accepting processes are first in, first out
  Remove upgrade-related code
  Be less parallel in traffic suite
  Increase send/receive buffers for testsuite SCTP listeners
  Decrease unnecessarily long testsuite timetraps
  Simplify accepting transport start
  Simplify peeloff signaling
  Simplify socket close at terminate
  Don't monitor listener after peeloff
  Don't receive initial messages out of order
  Remove assumption that SCTP association ids will be unique

* anders/diameter/grouped_errors/OTP-12721:
  Fix decode of Grouped AVPs containing errors
  Simplify logic
  Simplify logic

Without a timeout, TCP/SCTP connect can take some time to fail, which
resulted in failures in the pool suite after the parent commit fixed the
previously faulty sctp-first-then-tcp connect.

At the current count, there are 128 groups run in parallel, each of
which runs 52 testcases in parallel. That makes for 128*52 = 6656
testcases, which is probably also a factor in the sporadic failures
addressed by the parent commit. Don't run the 128 groups in parallel.

The defaults result in sporadic timeouts in the traffic suite after
testing over SCTP was added in commit fadf753b. The behaviour looks to
be specific to SLES 11, and is presumably the same resends/congestion
that lead to the buffers being increased in the gen_sctp suite in commit
12febf13 (and commented in commit e931991f).  The behaviour hasn't been
seen on SLES 10.

RFC 6733 says this of Failed-AVP in 7.5:

   In the case where the offending AVP is embedded within a Grouped AVP,
   the Failed-AVP MAY contain the grouped AVP, which in turn contains
   the single offending AVP.  The same method MAY be employed if the
   grouped AVP itself is embedded in yet another grouped AVP and so on.
   In this case, the Failed-AVP MAY contain the grouped AVP hierarchy up
   to the single offending AVP.  This enables the recipient to detect
   the location of the offending AVP when embedded in a group.

It says this of DIAMETER_INVALID_AVP_LENGTH in 7.1.5:

      The request contained an AVP with an invalid length.  A Diameter
      message indicating this error MUST include the offending AVPs
      within a Failed-AVP AVP.  In cases where the erroneous AVP length
      value exceeds the message length or is less than the minimum AVP
      header length, it is sufficient to include the offending AVP
      header and a zero filled payload of the minimum required length
      for the payloads data type.  If the AVP is a Grouped AVP, the
      Grouped AVP header with an empty payload would be sufficient to
      indicate the offending AVP.  In the case where the offending AVP
      header cannot be fully decoded when the AVP length is less than
      the minimum AVP header length, it is sufficient to include an
      offending AVP header that is formulated by padding the incomplete
      AVP header with zero up to the minimum AVP header length.

The AVPs placed in the errors field of a diameter_packet record are
intended to be appropriate for inclusion in a Failed-AVP, but neither of
the above paragraphs has been followed in the Grouped case: the entire
faulty AVP (non-faulty components and all) has been included. This made
it impossible to identify the actual faulty AVP in all but simple case.

This commit adapts the decode to the RFC, and implements the suggested
single faulty AVP, nested in as many Grouped containers as required.
The best-effort decode of Failed-AVP in answer messages, initially
implemented in commit 0f9cdbaf, is also applied.