Previously, if a script called by provision threw an error, the
traceback for the called script would be lost far above the traceback
from provision itself in the terminal history, resulting in a great
deal of confusion about what the actual problem was.
Before this commit, provisioning was done by executing provision.py,
which printed the log directly to stdout, making debugging harder.
This commit creates a wrapper bash script 'provision' in tools, which
calls 'zulip/scripts/tools/provision_vm.py' (the new location of
provision.py) and prints all the output to
'zulip/var/log/zulip/zulip_provision.log' via 'tee'.
Travis tests and docs have been modified accordingly.
Tim Abbott
Robert Hönig
Tim Abbott
Anders Kaseorg
Luke Faraone