Fix bug with setting ordered_scan plan result after task combining.
Fix bug with setting ordered_scan plan result after task combining.

Ordered scans are useful for fault tolerance but not possible in how
we deal with combined tasks. If a single task has multiple ranges, it
is non-deterministic the order we read them (this is good, let's us
schedule better).

Change-Id: I3bc673dcacb41f2150c1d037e552069e59229ccf
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/8373
Tested-by: jenkins
Reviewed-by: Chao Sun <67a7c7fa38d7a5d78492d6f0626602205a411205@cloudera.com>

cloudera/recordservice,cloudera/recordservice,cloudera/recordservice,cloudera/recordservice,cloudera/recordservice,cloudera/recordservice,cloudera/recordservice