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()
@@ -2487,9 +2485,13 @@ bool CBanDB::Read(banmap_t& banSet)
 
 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);