move ThreadFlushWalletDB declaration to walletdb.h

src/wallet/db.h

@@ -25,9 +25,6 @@ class COutPoint;
 
 extern unsigned int nWalletDBUpdated;
 
-void ThreadFlushWalletDB(const std::string& strWalletFile);
-
-
 class CDBEnv
 {
 private:

src/wallet/walletdb.h

@@ -138,5 +138,6 @@ private:
 };
 
 bool BackupWallet(const CWallet& wallet, const std::string& strDest);
+void ThreadFlushWalletDB(const std::string& strFile);
 
 #endif // BITCOIN_WALLETDB_H