reboot-ping-pong: Cope with un-encodable output sequences

By dropping them on the floor.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I3af6820dd00c7c81b2a3f91853f8f22d55d520ca
diff --git a/amboar/obmc-scripts/reboot-ping-pong/rpp b/amboar/obmc-scripts/reboot-ping-pong/rpp
index 99eae0a..c4940a9 100755
--- a/amboar/obmc-scripts/reboot-ping-pong/rpp
+++ b/amboar/obmc-scripts/reboot-ping-pong/rpp
@@ -52,7 +52,10 @@
 
 class PexpectLogger(object):
     def write(self, bstring):
-        sys.stdout.write(bstring.decode())
+        try:
+            sys.stdout.write(bstring.decode())
+        except UnicodeDecodeError:
+            print("Dropping broken unicode line")
 
     def flush(self):
         sys.stdout.flush()