[PATCH 4 of 6] packaging: builddeb's cleanup needs to expand PWD, safely

[Antonio Muci]

# HG changeset patch
# User muxator <a.mux at inwind.it>
# Date 1539116315 -7200
#      Tue Oct 09 22:18:35 2018 +0200
# Node ID 374fcdd01ef6b813d578d865eaccb94d3cda5dc8
# Parent  186a840796aae2aa48ca5228fc7225779e3e0ee9
packaging: builddeb's cleanup needs to expand PWD, safely

Single quotes would not expand the variable.

diff --git a/contrib/packaging/builddeb b/contrib/packaging/builddeb
--- a/contrib/packaging/builddeb
+++ b/contrib/packaging/builddeb
@@ -16,7 +16,7 @@ DEBFLAGS=-b
 
 cleanup() {
     if [ '$CLEANUP' ]; then
-        rm -r '$PWD/debian';
+        rm -r "$PWD/debian";
     fi
 }