Fix share_table_files bug

Summary: constructor wasn't properly constructing BackupableDBOptions

Test Plan: no test

Reviewers: benj

Reviewed By: benj

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16749

include/utilities/backupable_db.h

@@ -64,6 +64,7 @@ struct BackupableDBOptions {
                                bool _destroy_old_data = false)
       : backup_dir(_backup_dir),
         backup_env(_backup_env),
+        share_table_files(_share_table_files),
         info_log(_info_log),
         sync(_sync),
         destroy_old_data(_destroy_old_data) {}