Use $(..) instead of `..`,
use && and || instead of -a and -o,
double quote to prevent word splitting,
handle cd failure.

Change-Id: I860891323a81ac4a46c868ab028df1e1f837c115
Reviewed-on: https://gerrit.libreoffice.org/33897Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: jan iversen <jani@documentfoundation.org>