Merge branch 'stable-4.9'

* stable-4.9:
  PackInserter: Implement newReader()
  Move some strings from DfsText to JGitText
  FileRepository: Add pack-based inserter implementation
  ObjectDirectory: Factor a method to close open pack handles
  ObjectDirectory: Remove last modified check in insertPack

Change-Id: Ifc9ed6f5d8336bc978818a64eae122bceb933e5d

diff --cc org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
Simple merge

diff --cc org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
Simple merge