kgio 2.8.1 - minor improvements and test fixes

Improved error reporting for kgio_accept/kgio_tryaccept.
Minor size reduction throughout.  There are also several
test case fixes for race conditions.

Thanks to Hleb Valoshka and the Debian project for all the
help with this release!

Eric Wong (7):
      check syscall returns against < 0 instead of == -1
      accept: more informative exception on unknown family
      test_tryopen: skip EACCES test when euid == 0
      test/lib_read_write: account for larger-than-normal pipes
      test_poll: avoid potentially thread-unsafe test
      test_poll: preserve original trap(:USR1) handler
      test_poll: be less dependent on signal handler ordering

Hleb Valoshka (4):
      Change prefix of temporary sockets to prevent races
      Don't dump 20M in case of failure
      Create own directory for every unix socket in unit tests
      Close tempfile and unlink it immediately.