#1378 [RTM] Fix issue #1376 - catch db error on bootup (state: open)

Description

When there has been an error checking the tables on bootup, the exception was not being catched. Instead it broke the whole install process due to the newly added migrations.

Checklist

• [X] Read and understood the CONTRIBUTING guidelines
• [X] All tests passing
• [X] Checked the changes with phpcq and introduced no new issues

@stefanheimes pls merge and tag