Fixed TypeError in database launch error handle

openstack_dashboard.dashboards.project.databases.workflows.create_instance
in populate_flavor_choices

TypeError: 'NoneType' object is not iterable

If there's an exception in
openstack_dashboard/dashboards/project/databases/workflows/create_instance.py
SetInstanceDetailsAction.flavors, the follow-on method will have a
TypeError.

[code]
    @memoized.memoized_method
    def flavors(self, request):
        try:
            return api.trove.flavor_list(request)
        except Exception:
            LOG.exception("Exception while obtaining flavors list")
            self._flavors = []

    def populate_flavor_choices(self, request, context):
        flavor_list = [(f.id, "%s" % f.name) for f in self.flavors(request)]
        return sorted(flavor_list)
[code]

if self.flavors has an error, it will eventually return a None.

There's 2 options here:
A) return an empty list
B) redirect to another page

I have to believe that returning an empty list will be more confusing
than a redirect, so I'd like to handle this with exceptions.handle.

Change-Id: I9aff36875c26958ab8ef1f99828ed6113216c3c3
Closes-Bug: 1306815
Fix instance flavor popover table

The instance flavor popover table is not rendered.

Change-Id: I6710fa550a95659cbf5dbf8c6cf29691cfa161fe
Closes-bug: 1354230
Ability to create data sources from job launch

Adding the ability to generate data sources from
within the job launch modal.
* Change to DynamicChoiceField for input and output
* Changed workflow for data source to properly set
  workflow.object

Change-Id: I7d3b7bbd94c50f5e70a7e70bdb6d4a86475e1a6e
Closes-Bug: #1346931
Make some new strings translator friendly

_usage_summary.html:
blocktrans contains non-simple HTML tags and the range
of blocktrans seems natural. This commit split blocktrans
into the start and end part of the period.

templates/images/properties/_edit.html:
The sensence and the value are concatenated in the code
and translators cannot control the word order.

Change-Id: I3021d67dcb20968b785a8a98ed639a128e3412f2
Closes-Bug: #1354125
Imported Translations from Transifex

Change-Id: I7c621e77a9f39424eeee8c022abea28bf116de1b
Merge "Fix instance flavor popover table"
Cleans up the translation

Replaces translation.ungettext_lazy with
ungettext_lazy by importing ungettext_lazy from django.utils.translation
Replaces translation.ugettext_lazy with _
by importing ugettext_lazy as _ from django.utils.translation

Closes-Bug: 1351478

Change-Id: I1b0415bcd5d9b5b0e3f1328f0289c4ca381e02cd
Merge "Ability to create data sources from job launch"
Merge "Fixed TypeError in database launch error handle"
Merge "Cleans up the translation"
Merge "Make some new strings translator friendly"