Merge branch 'stable-5.5' into stable-5.6

* stable-5.5:
  Prepare 5.3.9-SNAPSHOT builds
  JGit v5.3.8.202011260953-r
  Prepare 5.1.15-SNAPSHOT builds
  JGit v5.1.14.202011251942-r
  GC#deleteOrphans: log warning for deleted orphaned files
  GC#deleteOrphans: handle failure to list files in pack directory
  Ensure that GC#deleteOrphans respects pack lock
  Update API warning filters
  Remove unused imports

Change-Id: I00c8ddad0059a20a978743dfb7ad1b513dc7fef6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

diff --cc org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollectorTest.java
Simple merge

diff --cc org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
index 78b830e649cbb4c9624de88e2271a886116208dd,e54c4ad458431ff18e1b3a671bf6322f746e8398..bbbe3b965760cc90aa975263ab89ea2add9ba728
--- 1/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
--- 2/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcOrphanFilesTest.java
@@@ -53,17 -53,21 +53,21 @@@ import org.junit.Before
  import org.junit.Test;
  
  public class GcOrphanFilesTest extends GcTestCase {
 -      private final static String PACK = "pack";
 +      private static final String PACK = "pack";
  
 -      private final static String BITMAP_File_1 = PACK + "-1.bitmap";
 +      private static final String BITMAP_File_1 = PACK + "-1.bitmap";
  
+       private static final String BITMAP_File_2 = PACK + "-2.bitmap";
+ 
        private static final String IDX_File_2 = PACK + "-2.idx";
  
 -      private final static String IDX_File_malformed = PACK + "-1234idx";
 +      private static final String IDX_File_malformed = PACK + "-1234idx";
  
+       private static final String KEEP_File_2 = PACK + "-2.keep";
+ 
        private static final String PACK_File_2 = PACK + "-2.pack";
  
 -      private final static String PACK_File_3 = PACK + "-3.pack";
 +      private static final String PACK_File_3 = PACK + "-3.pack";
  
        private File packDir;
  

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

diff --cc org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
Simple merge