Remove dead code.

The dead code has been in the codebase since the initial commit and is
generating a compiler warning when used in Xcode.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=164174594

db/version_set.cc

@@ -1399,13 +1399,6 @@ void VersionSet::SetupOtherInputs(Compaction* c) {
                                    &c->grandparents_);
   }
 
-  if (false) {
-    Log(options_->info_log, "Compacting %d '%s' .. '%s'",
-        level,
-        smallest.DebugString().c_str(),
-        largest.DebugString().c_str());
-  }
-
   // Update the place where we will do the next compaction for this level.
   // We update this immediately instead of waiting for the VersionEdit
   // to be applied so that if the compaction fails, we will try a different