CBQE-1090: fix 'sudo: cd: command not found'

Change-Id: I5bcee54f6fa0c223b8988a16d19c64a4fe599989
Reviewed-on: http://review.couchbase.org/25256
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>