Make -o option required if using 'test' command

Fixes bug 1250939

If the -o option isn't specified, then the code will end up updating the
jobs instead of outputting the XML to a directory. That can be a fairly
big surprise.

Change-Id: I3b84b097ea7fc96c18aa2d49b3bff246833822a6
Merge "Make -o option required if using 'test' command"