+5930. [bug] Fix DiG query retry and fail-over bug in UDP mode.
+ Also simplify the overall retry and fail-over logic to
+ make it behave predictably, and always respect the
+ documented +retry/+tries count set by a command-line
+ option (or use the default values of 2 or 3
+ respectively). [GL #3407]
+
5927. [bug] A race was possible in dns_dispatch_connect()
that could trigger an assertion failure if two
threads called it near-simultaneously. [GL #3456]