DBImpl::CheckConsistency() shouldn't create path name with double "/"

Summary: GetLiveFilesMetaData() already adds a leading "/" in file name. No need to add one extra "/" in DBImpl::CheckConsistency()

Test Plan: make all check

Reviewers: yhchiang, rven, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D31779

db/db_impl.cc

@@ -3530,7 +3530,8 @@ Status DBImpl::CheckConsistency() {
 
   std::string corruption_messages;
   for (const auto& md : metadata) {
-    std::string file_path = md.db_path + "/" + md.name;
+    // md.name has a leading "/".
+    std::string file_path = md.db_path + md.name;
 
     uint64_t fsize = 0;
     Status s = env_->GetFileSize(file_path, &fsize);