Misc fixes on Python tools (#2136)

Misc fixes on Python tools
diff --git a/tools/biotop.py b/tools/biotop.py
index 2aab1fc..3fe454c 100755
--- a/tools/biotop.py
+++ b/tools/biotop.py
@@ -53,7 +53,7 @@
 diskstats = "/proc/diskstats"
 
 # signal handler
-def signal_ignore(signal, frame):
+def signal_ignore(signal_value, frame):
     print()
 
 # load BPF program