Merge #7959: fix race that could fail to persist a ban

f4ac02e fix race that could fail to persist a ban (Kaz Wesley)

src/net.cpp

@@ -2634,9 +2634,10 @@ void DumpBanlist()
 
     CBanDB bandb;
     banmap_t banmap;
+    CNode::SetBannedSetDirty(false);
     CNode::GetBanned(banmap);
-    if (bandb.Write(banmap))
+    if (!bandb.Write(banmap))
-        CNode::SetBannedSetDirty(false);
+        CNode::SetBannedSetDirty(true);
 
     LogPrint("net", "Flushed %d banned node ips/subnets to banlist.dat  %dms\n",
         banmap.size(), GetTimeMillis() - nStart);