db: make db_exec() an internal function.

Every caller is using prepared statements now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

wallet/db.c

@@ -161,7 +161,7 @@ static void db_do_exec(const char *caller, struct db *db, const char *cmd)
 	}
 }
 
-void PRINTF_FMT(3, 4)
+static void PRINTF_FMT(3, 4)
     db_exec(const char *caller, struct db *db, const char *fmt, ...)
 {
 	va_list ap;

wallet/db.h

@@ -38,12 +38,6 @@ struct db *db_setup(const tal_t *ctx);
 sqlite3_stmt *PRINTF_FMT(3, 4)
 	db_query(const char *caller, struct db *db, const char *fmt, ...);
 
-/**
- * db_exec - execute a statement, call fatal() if it fails.
- */
-void PRINTF_FMT(3, 4)
-	db_exec(const char *caller, struct db *db, const char *fmt, ...);
-
 /**
  * db_begin_transaction - Begin a transaction
  *