Fix broken DWA

Commit e762d7d1 broke outgoing DWA by setting new Hop-by-Hop and
End-to-End identifiers instead of those of the incoming DWR.
Fix handling of 5014, DIAMETER_INVALID_AVP_LENGTH

The error was detected as 5004 (DIAMETER_INVALID_AVP_VALUE) for
stringish Diameter types, in which case an AVP length that pointed past
the end of a message resulted in encode failure of the suggested
Failed-AVP.

Should have been fixed in commit 4ce2d3a6.
Merge branch 'anders/diameter/broken_dwa/OTP-11367' into anders/diameter/patch_release/OTP-11459

* anders/diameter/broken_dwa/OTP-11367:
  Fix broken DWA
Merge branch 'anders/diameter/5014_failure/OTP-11395' into anders/diameter/patch_release/OTP-11459

* anders/diameter/5014_failure/OTP-11395:
  Fix handling of 5014, DIAMETER_INVALID_AVP_LENGTH
Update appup, vsn -> 1.4.4
Merge branch 'anders/diameter/patch_release/OTP-11459' into maint-r16

* anders/diameter/patch_release/OTP-11459:
  Update appup, vsn -> 1.4.4
  Fix handling of 5014, DIAMETER_INVALID_AVP_LENGTH
  Fix broken DWA
Update release notes
Avoid serialization on code_server in xmerl:export()

The inheritance mechanism in xmerl used to use 'catch apply(M,F,Args)' to
try different modules M until one was found that had a function F/A.
However, when M:F/A does not exist, apply/3 will trap to
error_handler:undefined_function/3, which will call code:ensure_loaded(M),
making a synchronous request to the code server process. If many processes
tried to use xmerl:export() concurrently, they would get serialized waiting
for the code server process. This patch uses erlang:function_exported/3
instead to check if M:F/A exists. If M exists, it should already have been
loaded at that point due to the inheritance checking in the
xmerl:callbacks/1 function.
Merge branch 'richcarl/xmerl-avoid-code-server-serialization/OTP-11463' into maint

* richcarl/xmerl-avoid-code-server-serialization/OTP-11463:
  Avoid serialization on code_server in xmerl:export()
Merge branch 'maint'
Merge branch 'maint-r16' into maint
Merge branch 'maint'