all: replace non-leading tabs with spaces

We commonly only allow tabs at the beginning of a line, not
afterwards. The reason for this style is so that the code
looks formated right with tabstop=4 and tabstop=8.

examples/python/dbus/wifi-hotspot.py

@@ -54,7 +54,7 @@ con = dbus.Dictionary({
     'ipv6': s_ip6
      })
 
-def usage():	
+def usage():
     print("Usage: %s <ifname> [up|down]" % sys.argv[0])
     sys.exit(0)