[dovecot/core] eb8143: lib: Added o_stream_unix_write_fd() assert: fd>=0

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: eb8143d997a69e688c4349a47464c47837d3f53d
      https://github.com/dovecot/core/commit/eb8143d997a69e688c4349a47464c47837d3f53d
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2016-05-03 (Tue, 03 May 2016)

  Changed paths:
    M src/lib/ostream-unix.c

  Log Message:
  -----------
  lib: Added o_stream_unix_write_fd() assert: fd>=0