tx_pool: initialize bitflags padding since it gets written to storage

Avoids valgrind reporting uninitialized data usage

src/blockchain_db/blockchain_db.h

@@ -148,6 +148,7 @@ struct txpool_tx_meta_t
   uint8_t relayed;
   uint8_t do_not_relay;
   uint8_t double_spend_seen: 1;
+  uint8_t bf_padding: 7;
 
   uint8_t padding[76]; // till 192 bytes
 };

src/cryptonote_core/tx_pool.cpp

@@ -239,6 +239,7 @@ namespace cryptonote
         meta.relayed = relayed;
         meta.do_not_relay = do_not_relay;
         meta.double_spend_seen = have_tx_keyimges_as_spent(tx);
+        meta.bf_padding = 0;
         memset(meta.padding, 0, sizeof(meta.padding));
         try
         {
@@ -278,6 +279,7 @@ namespace cryptonote
       meta.relayed = relayed;
       meta.do_not_relay = do_not_relay;
       meta.double_spend_seen = false;
+      meta.bf_padding = 0;
       memset(meta.padding, 0, sizeof(meta.padding));
 
       try