Merge branch 'stable-5.1'

* stable-5.1:
  Fix DescribeCommand with multiple match options
  Fix git-describe tie-breakers

Change-Id: I64d9b0099fc0d8449ec08f0b5653572b5c2f840f
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

diff --cc org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
index bb0714d23396f092de30ff61e1eb9a9c94bc40d4,f2093e39403f2f6471e8bab416d2365c648ff51c..807079eb23c9b1da942c47f7827d32c6bd7d3353
--- 1/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
--- 2/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
@@@ -42,15 -42,14 +42,16 @@@
   */
  package org.eclipse.jgit.api;
  
 +import static java.nio.charset.StandardCharsets.UTF_8;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNull;
+ import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertTrue;
  
 +import java.io.BufferedWriter;
  import java.io.File;
 -import java.io.FileWriter;
  import java.io.IOException;
 +import java.nio.file.Files;
  import java.util.Arrays;
  import java.util.Collection;