Do a proper tls/ca cleanup in unstack

Certificates and the index were left in the data directory after
running unstack. That would break devstack on the next run.

partial blueprint devstack-https
Change-Id: I6eb552a76fb29addf4d02254c027e473d6805df1
XenAPI: Use GUEST_PASSWORD when installing DomU

We know what the GUEST_PASSWORD will be, so set it during DomU
installation; therefore if the installation fails for any reason
we have a correct GUEST_PASSWORD set rather than the obscure and
undocumented 'r00tme'

Change-Id: I684646a74f2cede43667a40556e247955e042ae4
XenAPI: Always add latest Cirros euc image

Some tests, such as test_minimum_basic_scenario, assume qcow and if
a qcow image does not exit, falls back to the euc image.
This change ensures these tests work in the stock XenServer environment.

Change-Id: I718f178f7e5e0fa4eebd17a49caf5254124092e3
Merge "Do a proper tls/ca cleanup in unstack"
Merge "XenAPI: Use GUEST_PASSWORD when installing DomU"
Merge "XenAPI: Always add latest Cirros euc image"