shellcheck fixes; closes #690

a small selection of changes from the PR

bin/bubbleparty.sh

@@ -9,7 +9,7 @@ bwrap \
   --dev-bind /dev /dev \
   --dir /tmp \
   --dir /var \
-  --bind $(pwd) $(pwd) \
+  --bind "$(pwd)" "$(pwd)" \
   --share-net \
   --die-with-parent \
   --file 11 /etc/passwd \

bin/prisonparty.sh

@@ -141,7 +141,7 @@ chmod 777 "$jail/tmp"
 
 
 # create a dev
-(cd $jail; mkdir -p dev; cd dev
+(cd "$jail"; mkdir -p dev; cd dev
 [ -e null ]    || mknod -m 666 null    c 1 3
 [ -e zero ]    || mknod -m 666 zero    c 1 5
 [ -e random ]  || mknod -m 444 random  c 1 8

copyparty/broker_util.py

@@ -2,7 +2,6 @@
 from __future__ import print_function, unicode_literals
 
 import argparse
-import traceback
 
 from queue import Queue