Allow for VmdbDatabase to not be present

[Fryguy]

This commit allows for the Ops screen to continue to work even if the VmdbDatabase record is not present. Right now, a VmdbDatabase record is required to be present so that this screen does not blow up, and so it is required during seeding. Seeding this table is expensive, so we want to delay it, but we can't unless the ops screen can handle that.

[Fryguy]

Once this PR is merged I will change the core to remove VmdbDatabase from seeding and find a different way to get it in (perhaps a one-time refresh on the queue on boot). cc @jrafanie @kbrock

[miq-bot]

Checked commit Fryguy@8c4a3aa with ruby 2.3.3, rubocop 0.47.1, and haml-lint 0.20.0
4 files checked, 2 offenses detected

app/controllers/ops_controller/db.rb

• ❗ - Line 103, Col 32 - Style/ExtraSpacing - Unnecessary spacing detected.
• ❗ - Line 104, Col 61 - Style/ExtraSpacing - Unnecessary spacing detected.