Fix errexit in lib/ldap

clear_ldap_state() deletes an object from the DIT that doesn't exist
on the first run, this is OK but fails with errexit enabled.

Change-Id: I3b881eedc891caa6b2dfd5913e43f3babcfa7d47
Update USB boot tools

* update tools/get_uec_image.sh for precise and proxy operation
* add cleanup to tools/warm_apts_and_pips_for_uec.sh, remove pip download
* run tools/warm_apts_and_pips_for_uec.sh as root
* update tools/build_ues_ramdisk.sh for precise; add exec sudo
* update tools/build_usb_boot.sh to use $DEST

Change-Id: If3cc0a8973805f0376dfce2bcbb75082f2e039d3
Merge branch 'ldap-errexit' into dt-test
Merge branch 'stop-swift-redux' into dt-test
Merge branch 'deprecate-opts' into dt-test
Merge branch 'set-conf-dir-1' into dt-test
Merge branch 'set-conf-dir-2' into dt-test
Merge branch 'test-service-functions' into dt-test
Merge branch 'move-create-accounts' into dt-test
Merge branch 'update-usb-tools' into dt-test