[dbapi] Stop shadowing exceptions in get_repository() (closes #2710515) Exceptions are already handled higher up in the stack so there's no reason to handle them here. Furthermore, non-ConnectionError exceptions would get hidden, making debugging harder.

bgcolor = '#000000'
stylesheets = ['%s/cubicweb.css' % datadir_url]
logo = '%s/logo.png' % datadir_url
lazy = lazystr('%(bgcolor)s')