[SPARK-5147][Streaming] Delete the received data WAL log periodically

This is a refactored fix based on jerryshao 's PR #4037
This enabled deletion of old WAL files containing the received block data.
Improvements over #4037
- Respecting the rememberDuration of all receiver streams. In #4037, if there were two receiver streams with multiple remember durations, the deletion would have delete based on the shortest remember duration, thus deleting data prematurely for the receiver stream with longer remember duration.
- Added unit test to test creation of receiver WAL, automatic deletion, and respecting of remember duration.

jerryshao I am going to merge this ASAP to make it 1.2.1 Thanks for the initial draft of this PR. Made my job much easier.

Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: jerryshao <saisai.shao@intel.com>

Closes #4149 from tdas/SPARK-5147 and squashes the following commits:

730798b [Tathagata Das] Added comments.
c4cf067 [Tathagata Das] Minor fixes
2579b27 [Tathagata Das] Refactored the fix to make sure that the cleanup respects the remember duration of all the receiver streams
2736fd1 [jerryshao] Delete the old WAL log periodically

0 files changed, 0 insertions, 0 deletions