fluent/fluentd — pull request #308 by tagomoris (2014-04-25 09:52:27+00:00)
Title: Add dummy log device and fix to use it

* remove setting global logger in lib/fluent/test.rb
* developer cannot understand when this assignment happen
* global logger assignment exists in test/helper
* dummy logger should contain messages that logger writes
* to assert logger's output from core/plugin tests
* test dummy logger is set in default in create_driver
* to test logger message in configure