Remove reference to non-existing entry in FILENAMES:

An entry with key "legacy_fontlist" is never created, the lookup for it will yield an empty string.
Open an empty path will always fail, so the then-block is never run.

Therefor this removes that dead code completely.

src/sdltiles.cpp

@@ -3266,21 +3266,8 @@ static cata::optional<std::string> find_system_font( const std::string &name, in
     const std::string fontlist_path = FILENAMES["fontlist"];
     std::ifstream fin( fontlist_path.c_str() );
     if( !fin.is_open() ) {
-        // Try opening the fontlist at the old location.
-        fin.open( FILENAMES["legacy_fontlist"].c_str() );
-        if( !fin.is_open() ) {
-            dbg( D_INFO ) << "Generating fontlist";
-            assure_dir_exist( FILENAMES["config_dir"] );
-            save_font_list();
-            fin.open( fontlist_path.c_str() );
-            if( !fin ) {
-                dbg( D_ERROR ) << "Can't open or create fontlist file " << fontlist_path;
-                return cata::nullopt;
-            }
-        } else {
-            // Write out fontlist to the new location.
-            save_font_list();
-        }
+        // Write out fontlist to the new location.
+        save_font_list();
     }
     if( fin.is_open() ) {
         std::string fname;