Flush wallet storage once for a sequence of puts.

This speeds up save_transactions by 2 to 3 times for me.

lib/wallet.py

@@ -202,10 +202,11 @@ class Abstract_Wallet(object):
             tx = {}
             for k,v in self.transactions.items():
                 tx[k] = str(v)
-            self.storage.put('transactions', tx)
-            self.storage.put('txi', self.txi)
-            self.storage.put('txo', self.txo)
-            self.storage.put('pruned_txo', self.pruned_txo)
+            # Flush storage only with the last put
+            self.storage.put('transactions', tx, False)
+            self.storage.put('txi', self.txi, False)
+            self.storage.put('txo', self.txo, False)
+            self.storage.put('pruned_txo', self.pruned_txo, True)
 
     def clear_history(self):
         with self.transaction_lock:
@@ -1263,8 +1264,8 @@ class Deterministic_Wallet(Abstract_Wallet):
         else:
             self.use_encryption = False
 
-        self.storage.put('seed', self.seed, True)
-        self.storage.put('seed_version', self.seed_version, True)
+        self.storage.put('seed', self.seed, False)
+        self.storage.put('seed_version', self.seed_version, False)
         self.storage.put('use_encryption', self.use_encryption,True)
 
     def get_seed(self, password):
@@ -1718,7 +1719,7 @@ class OldWallet(Deterministic_Wallet):
 
     def create_watching_only_wallet(self, mpk):
         self.seed_version = OLD_SEED_VERSION
-        self.storage.put('seed_version', self.seed_version, True)
+        self.storage.put('seed_version', self.seed_version, False)
         self.storage.put('master_public_key', mpk, True)
         self.create_account(mpk)