Adds a more helpful config failure message.
Adds a more helpful config failure message.

It will show the list of paths search for a config file if one could not
be found.

nivertech/nfldb,verdimrc/nfldb,codeaudit/nfldb,BurntSushi/nfldb,codeaudit/nfldb,nivertech/nfldb,bparafina/nfldb,verdimrc/nfldb,bparafina/nfldb,BurntSushi/nfldb