Generate quantum_metadata_proxy_shared_secret during proposal create

Also provide it to other barclamps (quantum).
Add library search_env_filtered

Provides a search that automatically applies an "env_filter", i.e. doing
a search against the correct proposal. To make this work,
nova/db/database_instance had to move to nova/database_instance (in line
with _all_ other *_instance entries in JSON files).

As a nice side effect, most previously broken env_filter get fixed
automatically. Before, some search() invocations re-(ab)used env_filters
from previous searches for entirely different barclamps. This should
help re-supporting multi-proposal in the future.

This approach should work for other barclamps too, but with Crowbar's
current architecture, each would have to ship it's own copy of this
library. A follow-up commit could move this to a more appropriate
(shared) location.
webui: Remove libvirt_type from UI that got added back by accident

This got added back on rebasing a patch, but shouldn't: this is now
handled by roles.
Allow to auto-generate self-signed SSL certificates

The setup is rather simple. Instead of a full-blown CA, a CSR is used
to create the self-signed certificate.
Stop comparing md5 to know if qemu.conf got changed

This partially reverts 72fb4e7c.

Chef::Util::FileEdit is now fixed so there's no need to do that hack
anymore.
Merge pull request #203 from vuntz/suse-only-no-md5

https://github.com/crowbar/barclamp-nova/pull/203

Merged by devtool for cloudsleuth
Gota get nova working under Ubuntu again.
Merge pull request #204 from cloudsleuth/pull-req-release-pebbles-master-f261f6b06f7679f7c4b2e8009725e349c085fcfd

Fix nova - libvirtd declared outside of SUSE block - fixed. [1/1]
Merge pull request #197 from saschpe/release/pebbles/master-lib-searchenvfiltered

Add library search_env_filtered
Merge pull request #198 from saschpe/release/pebbles/master-quantummetadataproxysharedsecret

Generate quantum_metadata_proxy_shared_secret during proposal create
Merge pull request #201 from vuntz/revert-libvirt-type

webui: Remove libvirt_type from UI that got added back by accident
Merge pull request #202 from saschpe/release/pebbles/master-ssl-gencerts

Allow to auto-generate self-signed SSL certificates