chainntnfs: switch debug tag to dev

This avoids collisions with the logging level tags

chainntnfs/interface_dev.go

@@ -0,0 +1,15 @@
+// +build dev
+
+package chainntnfs
+
+import "github.com/btcsuite/btcd/chaincfg/chainhash"
+
+// TestChainNotifier enables the use of methods that are only present during
+// testing for ChainNotifiers.
+type TestChainNotifier interface {
+	ChainNotifier
+
+	// UnsafeStart enables notifiers to start up with a specific best block.
+	// Used for testing.
+	UnsafeStart(int32, *chainhash.Hash, int32, func() error) error
+}