Merge branch 'stable-3.1'

* stable-3.1:
  PathToLockId: Refactor to use a FunctionalInterface
  LfsAuthUserProvider: Refactor to avoid name hiding
  LfsLocksHandle: Collapse duplicate if-block
  LfsLocksHandler: Simplify lambda expression
  LfsLocksHandler: Call Optional#isPresent before #get
  Use Truth8 to assert about Optional#isPresent
  LfsCipherTest: Extract repeated string to a constant
  InitLfs: Remove unnecessary empty overridden method
  LfsSshAuth: Remove redundant 'throws' declaration
  LfsGson: Remove unnecessary 'throws' declarations
  LfsDateTime: Add private constructor to hide default constructor
  Remove LfsDateTimeTest and dependency on joda-time
  Bazel: Mark joda-time as test only

Change-Id: I37393a8e50b2f8c014f366dcfc660e4759d4760d