Remove DEFAULT_STACK_USER, just use STACK_USER

STACK_USER needs to be set for more than just stack.sh, there
was no real distinction for using DEFAULT_STACK_USER instead
of just setting STACK_USER directly in stackrc and allowing it
to be overridden in localrc.

Change-Id: I9e8d70db29bb421f1ce3dbf40a5ad299cc7ea785
diff --git a/tools/copy_dev_environment_to_uec.sh b/tools/copy_dev_environment_to_uec.sh
index add4ff6..3fd4423 100755
--- a/tools/copy_dev_environment_to_uec.sh
+++ b/tools/copy_dev_environment_to_uec.sh
@@ -46,13 +46,13 @@
 # Create a stack user that is a member of the libvirtd group so that stack
 # is able to interact with libvirt.
 chroot $STAGING_DIR groupadd libvirtd || true
-chroot $STAGING_DIR useradd $DEFAULT_STACK_USER -s /bin/bash -d $DEST -G libvirtd || true
+chroot $STAGING_DIR useradd $STACK_USER -s /bin/bash -d $DEST -G libvirtd || true
 
 # Add a simple password - pass
-echo $DEFAULT_STACK_USER:pass | chroot $STAGING_DIR chpasswd
+echo $STACK_USER:pass | chroot $STAGING_DIR chpasswd
 
 # Configure sudo
-( umask 226 && echo "$DEFAULT_STACK_USER ALL=(ALL) NOPASSWD:ALL" \
+( umask 226 && echo "$STACK_USER ALL=(ALL) NOPASSWD:ALL" \
     > $STAGING_DIR/etc/sudoers.d/50_stack_sh )
 
 # Copy over your ssh keys and env if desired
@@ -67,7 +67,7 @@
 cp_it . $STAGING_DIR/$DEST/devstack
 
 # Give stack ownership over $DEST so it may do the work needed
-chroot $STAGING_DIR chown -R $DEFAULT_STACK_USER $DEST
+chroot $STAGING_DIR chown -R $STACK_USER $DEST
 
 # Unmount
 umount $STAGING_DIR