[logback-dev] [qos-ch/logback] 30d2f7: Fix JUL logger level reset (LOGBACK-906)

[Tony Trinh]

  Branch: refs/heads/master
  Home:   https://github.com/qos-ch/logback
  Commit: 30d2f7716c6739ce4e05da1c69fefdee0171a5e4
      https://github.com/qos-ch/logback/commit/30d2f7716c6739ce4e05da1c69fefdee0171a5e4
  Author: Tony Trinh <tony19 at gmail.com>
  Date:   2013-10-03 (Thu, 03 Oct 2013)

  Changed paths:
    M logback-classic/src/main/java/ch/qos/logback/classic/Logger.java
    M logback-classic/src/main/java/ch/qos/logback/classic/jul/JULHelper.java
    M logback-classic/src/test/java/ch/qos/logback/classic/jul/LevelChangePropagatorTest.java

  Log Message:
  -----------
  Fix JUL logger level reset (LOGBACK-906)

A NullPointerException occurred when setting a JUL logger's level to
null, which should have reset the logger level to the parent's effective
level. The null level was incorrectly propagated to context listeners,
leading to the NPE.

This patch propagates the logger's parent effective level.