Merge branch 'stable-5.9' into stable-5.10

* stable-5.9:
  Remove unused imports
  Silence API warnings
  Remove erraneously merged source features
  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
  PacketLineIn: ensure that END != DELIM
  Update API warning filters
  Remove unused imports

Change-Id: Icf415ac5bab2f69f71189c942424ee69f8a64d4e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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
index 741d86e67fb6bd6f60be4b56ae141ebe7923daa4,c18a1895c360ae3f6207d8476bd3fc446b899001..1f2fe1057fcd38d5b28dae275336a5dc25a4ed37
--- 1/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
--- 2/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
@@@ -978,8 -984,9 +984,10 @@@ public class GC 
                        } else {
                                if (base == null || !n.startsWith(base)) {
                                        try {
-                                               FileUtils.delete(packDir.resolve(n).toFile(),
+                                               Path delete = packDir.resolve(n);
 -                                              Files.delete(delete);
++                                              FileUtils.delete(delete.toFile(),
 +                                                              FileUtils.RETRY | FileUtils.SKIP_MISSING);
+                                               LOG.warn(JGitText.get().deletedOrphanInPackDir, delete);
                                        } catch (IOException e) {
                                                LOG.error(e.getMessage(), e);
                                        }