[PATCH 1 of 6 STABLE] dockerdeb: elimate 'cd' in export command

[Sean Farley]

# HG changeset patch
# User Sean Farley <sean at farley.io>
# Date 1460914600 25200
#      Sun Apr 17 10:36:40 2016 -0700
# Branch stable
# Node ID db33d0e7476c79ac0bc8048992ec6d24d6062c87
# Parent  97811ff7964710d32cae951df1da8019b46151a2
# EXP-Topic ppa
dockerdeb: elimate 'cd' in export command

This had the unfortunate side effect of causing the environment to have a
newline due to the fact that some 'cd' outputs the result of the directory
change.

diff --git a/contrib/dockerdeb b/contrib/dockerdeb
--- a/contrib/dockerdeb
+++ b/contrib/dockerdeb
@@ -2,11 +2,11 @@
 
 . $(dirname $0)/dockerlib.sh
 . $(dirname $0)/packagelib.sh
 
 BUILDDIR=$(dirname $0)
-export ROOTDIR=$(cd $BUILDDIR/..; pwd)
+export ROOTDIR=$(dirname $(readlink -f $BUILDDIR))
 
 checkdocker
 
 DISTID="$1"
 CODENAME="$2"