banlist (bugfix): allow CNode::SweepBanned() to run on interval

- allows CNode::SweepBanned() to run, even if !CNode::BannedSetIsDirty(),
  because if nBanUntil is over we want the ban to be disabled for these
  nodes

src/net.cpp

@@ -1455,9 +1455,7 @@ void DumpAddresses()
 void DumpData()
 {
     DumpAddresses();
-
-    if (CNode::BannedSetIsDirty())
-        DumpBanlist();
+    DumpBanlist();
 }
 
 void static ProcessOneShot()
@@ -2474,22 +2472,26 @@ bool CBanDB::Read(banmap_t& banSet)
         // ... verify the network matches ours
         if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
             return error("%s: Invalid network magic number", __func__);
-        
+
         // de-serialize address data into one CAddrMan object
         ssBanlist >> banSet;
     }
     catch (const std::exception& e) {
         return error("%s: Deserialize or I/O error - %s", __func__, e.what());
     }
-    
+
     return true;
 }
 
 void DumpBanlist()
 {
-    int64_t nStart = GetTimeMillis();
     CNode::SweepBanned(); // clean unused entries (if bantime has expired)
 
+    if (!CNode::BannedSetIsDirty())
+        return;
+
+    int64_t nStart = GetTimeMillis();
+
     CBanDB bandb;
     banmap_t banmap;
     CNode::GetBanned(banmap);