message: Update comment to reflect pcoinsTip is protected by cs_utxo
  This was missed in the passed locking changes where we moved
  away from using cs_main in the coins cache.
diff: @@ -548,7 +548,7 @@ bool ReconsiderBlock(CValidationState &state, CBlockIndex *pindex);
  /** The currently-connected chain of blocks (protected by cs_main). */
  extern CChain chainActive;
  -/** Global variable that points to the active CCoinsView (protected by cs_main) */
  +/** Global variable that points to the active CCoinsView (protected by cs_utxo) */
  extern CCoinsViewCache *pcoinsTip;
  /** Global variable that points to the active block tree (protected by cs_main) */
  