create_test_model does not catch failures
create_test_model does not catch failures

The previous behavior was to fall back to creating a new test model
from the salmonella sbml file.

JuBra/cobrapy,jerkos/cobrapy,zakandrewking/cobrapy,zakandrewking/cobrapy,jerkos/cobrapy,jeicher/cobrapy,JuBra/cobrapy,aebrahim/cobrapy,aebrahim/cobrapy,jeicher/cobrapy