process_bugs.py: handle LP timeouts gracefully

Launchpad timeouts all the time when modifying bugs with lots of tasks.
process_bugs should fail gracefully when it's in that unfortunately
common situation.
mpdelivery.sh: Fix TAGMSG syntax error

There was an error in TAGMSG variable setting, this fixes it.
create_milestones.py: support series creation

Support the creation of the series if it doesn't exist already and
the --createseries argument is passed. Status of the newly-created
series is set to "Future".

Additionally update the sample YAML file with icehouse projects.