Mark Task #19 as complete (apache#39)

Author: cbb330

task_list.json

@@ -467,7 +467,7 @@
       "Unit test: Concurrent scans on same fragment",
       "Unit test: No data corruption"
     ],
-    "status": "pending",
+    "status": "complete",
     "depends_on": [13],
     "priority": "P0"
   },