Handle exceptional case of data ftp or web site down

[matthewhanson]

from rob:
MODIS http and ftp goes down every wednesday for example. The MODIS fetch tests for server down and will kick you back out to the system if it's down under the assumption that you don't want it to continue your job if it can't do the --fetch as you have specified.

[matthewhanson]

That makes sense - if you specify fetch and it's down it should give it as an error message and not allow calling with --fetch.
Is that the way it works now for MODIS, or do I need to clean up the exception handling?