compaction: fix max_subcompactions option for CompactRange (#4082)

Summary:
The max_subcompactions option was introduced in https://github.com/facebook/rocksdb/pull/3775.
Closes https://github.com/facebook/rocksdb/pull/4082

Differential Revision: D8743258

Pulled By: ajkr

fbshipit-source-id: d60ee75769dfc19ab6f8754e4ff3a267848f1ed9

db/compaction_picker.cc

@@ -705,7 +705,7 @@ Compaction* CompactionPicker::CompactRange(
       GetCompressionType(ioptions_, vstorage, mutable_cf_options, output_level,
                          vstorage->base_level()),
       GetCompressionOptions(ioptions_, vstorage, output_level),
-      /* max_subcompactions */ 0, std::move(grandparents),
+      max_subcompactions, std::move(grandparents),
       /* is manual compaction */ true);
 
   TEST_SYNC_POINT_CALLBACK("CompactionPicker::CompactRange:Return", compaction);