Grant access to internal jgit package to org.eclipse.jgit.junit

This silences some discouraged access warnings issued since
TestRepository uses PackWriter which is in an internal package.

Change-Id: Ic9c4631e237c2fe1996c518328ecc2a9ab5c348b
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/META-INF/MANIFEST.MF

@@ -24,7 +24,8 @@ Export-Package: org.eclipse.jgit.api;version="3.2.0",
    org.eclipse.jgit.java7.test,
    org.eclipse.jgit.pgm",
  org.eclipse.jgit.internal.storage.pack;version="3.2.0";
-  x-friends:="org.eclipse.jgit.test,
+  x-friends:="org.eclipse.jgit.junit,
+   org.eclipse.jgit.test,
    org.eclipse.jgit.pgm",
  org.eclipse.jgit.lib;version="3.2.0",
  org.eclipse.jgit.merge;version="3.2.0",