PackFile: report correct message for checksum mismatch

When the packfile checksum does not match the expected one
report the correct checksum error instead of reporting that
the number of objects is incorrect.

Change-Id: I040f36dacc4152ae05453e7acbf8dfccceb46e0d
Signed-off-by: Luca Milanesio <luca.milanesio@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
(cherry picked from commit 436c99ce59)

org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties

 operationCanceled=Operation {0} was canceled
 outputHasAlreadyBeenStarted=Output has already been started.
 overflowedReftableBlock=Overflowed reftable block
-packChecksumMismatch=Pack checksum mismatch detected for pack file {0}
+packChecksumMismatch=Pack checksum mismatch detected for pack file {0}: .pack has {1} whilst .idx has {2}
 packCorruptedWhileWritingToFilesystem=Pack corrupted while writing to filesystem
 packDoesNotMatchIndex=Pack {0} does not match index
 packedRefsHandleIsStale=packed-refs handle is stale, {0}. retry

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java

 				} else if (!Arrays.equals(packChecksum, idx.packChecksum)) {
 					throw new PackMismatchException(MessageFormat.format(
 							JGitText.get().packChecksumMismatch,
-							packFile.getPath()));
+							packFile.getPath(), packChecksum,
+							idx.packChecksum));
 				}
 				loadedIdx = idx;
 			} catch (InterruptedIOException e) {
 		fd.readFully(buf, 0, 20);
 		if (!Arrays.equals(buf, packChecksum)) {
 			throw new PackMismatchException(MessageFormat.format(
-					JGitText.get().packObjectCountMismatch
-					, ObjectId.fromRaw(buf).name()
-					, ObjectId.fromRaw(idx.packChecksum).name()
-					, getPackFile()));
+					JGitText.get().packChecksumMismatch,
+					getPackFile(),
+					ObjectId.fromRaw(buf).name(),
+					ObjectId.fromRaw(idx.packChecksum).name()));
 		}
 	}