Fix bug in VersionEdit::DebugString()

db/version_edit.cc

@@ -355,7 +355,7 @@ std::string VersionEdit::DebugString(bool hex_key) const {
   }
   if (has_max_column_family_) {
     r.append("\n  MaxColumnFamily: ");
-    r.append(max_column_family_);
+    AppendNumberTo(&r, max_column_family_);
   }
   r.append("\n}\n");
   return r;