[ruby-cvs:78561] 6158e28f8d (master): [ruby/logger] Avoid creating [] and "" when logging an Exception that has no backtrace

Akira Matsuda	2019-07-31 14:38:38 +0900 (Wed, 31 Jul 2019)

  New Revision: 6158e28f8d

  https://github.com/ruby/ruby/commit/6158e28f8d

  Log:
    [ruby/logger] Avoid creating [] and "" when logging an Exception that has no backtrace
    
    https://github.com/ruby/logger/commit/75fd308053

  Modified files:
    lib/logger/formatter.rb