[xmlunit/xmlunit] a0c0d2: adapt failure message to `Schema` case

[GitHub <no...@gi...>]

  Branch: refs/heads/master
  Home:   https://github.com/xmlunit/xmlunit
  Commit: a0c0d27fd4f611cd8286fa9cd3f8d18b899bcf15
      https://github.com/xmlunit/xmlunit/commit/a0c0d27fd4f611cd8286fa9cd3f8d18b899bcf15
  Author: Stefan Bodewig <ste...@fr...>
  Date:   2016-11-02 (Wed, 02 Nov 2016)

  Changed paths:
    M RELEASE_NOTES.md
    M xmlunit-matchers/src/main/java/org/xmlunit/matchers/ValidationMatcher.java

  Log Message:
  -----------
  adapt failure message to `Schema` case

closes #89