add governance mode flag definition, tbd implementation

framework/libra-framework/sources/ol_sources/config/ol_features.move

@@ -1,14 +1,28 @@
 
 module ol_framework::ol_features_constants {
     use std::features;
-    /// Whether the new epoch trigger logic is enabled.
-    /// Lifetime: transient
-    const EPOCH_TRIGGER_ENABLED: u64 = 24;
-    public fun get_epoch_trigger(): u64 { EPOCH_TRIGGER_ENABLED }
-    public fun epoch_trigger_enabled(): bool {
-        features::is_enabled(EPOCH_TRIGGER_ENABLED)
-    }
+    ///////// KEEP COMMENTED ////////
+    // NOTE: this feature is deprecated
+    // since epoch trigger was an experimental feature
+    // but is permanent since v7.0.3.
+    // The code and ID are  kept here for reference
+    // /// Whether the new epoch trigger logic is enabled.
+    // /// Lifetime: transient
+    // const EPOCH_TRIGGER_ENABLED: u64 = 24;
+    // public fun get_epoch_trigger(): u64 { EPOCH_TRIGGER_ENABLED }
+    // public fun epoch_trigger_enabled(): bool {
+    //     features::is_enabled(EPOCH_TRIGGER_ENABLED)
+    // }
+
 
+    /// GOVERNANCE MODE
+    /// Certain transactions are disabled during deliberation and
+    /// execution of on-chain hot upgrades.
+    const GOVERNANCE_MODE_ENABLED: u64 = 25;
+    public fun get_governance_mode(): u64 { GOVERNANCE_MODE_ENABLED }
+    public fun is_governance_mode_enabled(): bool {
+        features::is_enabled(GOVERNANCE_MODE_ENABLED)
+    }
 
     //////// TEST HELPERS ////////
     #[test_only]