bump rep

[delivers #83638690]

Submodule src/github.com/cloudfoundry-incubator/rep fd70d74..a3f5b75:
  > Start task and run container asynchronously after allocating container and returning from Perform [#83638690]
  > Small fixes to tests around starting LRPs [#83638690]
  > Rep starts task in BBS before trying to run container
  > Rep responds to perform with success after reserving LRP container [#83638690]
  > Include tasks in auction-work log message

Signed-off-by: Kris Hicks <krishicks@gmail.com>