db_bench: --compaction_pri default should be rocksdb::Options().compaction_pri

Summary: Currently db_bnech's --compaction_pri default is set to be rocksdb::Options().compaction_style. Change it to rocksdb::Options().compaction_pri. Although, for now both is 0.

Test Plan: Build db_bench

Reviewers: anthony, rven, IslamAbdelRahman, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D49773

db/db_bench.cc

@@ -315,7 +315,7 @@ DEFINE_int32(compaction_style, (int32_t) rocksdb::Options().compaction_style,
              "style of compaction: level-based vs universal");
 
 static rocksdb::CompactionPri FLAGS_compaction_pri_e;
-DEFINE_int32(compaction_pri, (int32_t)rocksdb::Options().compaction_style,
+DEFINE_int32(compaction_pri, (int32_t)rocksdb::Options().compaction_pri,
              "priority of files to compaction: by size or by data age");
 
 DEFINE_int32(universal_size_ratio, 0,