fixup: prevent flipping "is banned" for the equal height

Consensus leans to ban it

Author: knst

src/masternode/meta.h

@@ -107,6 +107,9 @@ class CMasternodeMetaInfo
         if (height < m_platform_ban_updated) {
             return false;
         }
+        if (height == m_platform_ban_updated && !is_banned) {
+            return false;
+        }
         m_platform_ban = is_banned;
         m_platform_ban_updated = height;
         return true;