Merge branch 'master' into stable-4.0

Merge branch 'master' into stable-4.0

* master:
  Fix warnings in ObjectFilter
  Fix typo in reflog message written by RebaseCommand.tryFastForward()
  Correct @since tags for ObjectFilter
  Fix typo in ObjectWalk#getObjectFilter javadoc
  Allow ObjectWalk to be filtered by an arbitrary predicate
  Remove SoftReference from dfs.DeltaBaseCache
  Fix memory leak in dfs.DeltaBaseCase
  Update to Jetty 9.2.10
  Update javax.servlet to 3.1
  Use ANY_DIFF filter in ResolveMerger only for bare repositories
  FS_POSIX: Rework umask detection to make it settable
  Expose disposeBody() on RevCommit and RevTag
  ObjectReader: remove the walkAdvice API
  RevWalk: Discard uninteresting commits unless RevSort.BOUNDARY
  ObjectWalk: make setRetainBody(false) the default
  Do not concatenate strings as arguments to StringBuilder.append()
  IndexDiffFilter: Simplify a boolean expression
  GroupHead: Remove a redundant call to String.format()
  FS_Win32: Avoid an IOException on Windows if bash is not in PATH
  Skip logging stack trace on corrupt objects
  Add repository name to failures in HTTP server log
  Fix possible AIOOB in DirCacheTree.contains()
  Delete deprecated PackWriter.preparePack() methods
  Delete deprecated class IgnoreRule
  Delete deprecated checkoutEntry() methods in DirCacheCheckout
  Fix IllegalArgumentException in AmazonS3

Change-Id: Ica3d4f0675c81684fbe48fcf0053f2a949bc5c9b
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>