temporarily prefer bundled lz4 to test it

(cherry picked from commit bf6fa046508e1eea9c3388928ad1809bbcbf69f5)

setup.py

@@ -30,7 +30,7 @@ import setup_zstd
 import setup_b2
 
 # True: use the shared liblz4 (>= 1.7.0 / r129) from the system, False: use the bundled lz4 code
-prefer_system_liblz4 = True
+prefer_system_liblz4 = False
 
 # True: use the shared libzstd (>= 1.3.0) from the system, False: use the bundled zstd code
 prefer_system_libzstd = False