Fix userspace calling in hello_world

Author: r41k0u

BCC-Examples/hello_world.py

@@ -15,7 +15,9 @@ def LICENSE() -> str:
     return "GPL"
 
 
+# Compile and load
 b = BPF()
-b.load_and_attach()
+b.load()
+b.attach_all()
 
 trace_pipe()