db_init: don't abort if we cannot connect to the test database

[stefanv]

Often, in production, this database does not exist

[pep8speaks]

Hello @stefanv! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file tools/db_init.py:

Line 87:80: E501 line too long (84 > 79 characters)