fix k_1.zip for initial task files on Heidelbrain

[Optiligence]

It seems that *.k_1.zip files are not only generated on submission, but also for initial task files. Apparently there are also 2 ways to get a file from Heidelbrain which return different things with respect to the file attached to the task: /knossos/activeTask returns *.k.zip and *.nml respectively, so – i guess – the original file upload whereas /knossos/activeTask/lastSubmit always tries to provide a *.k.zip but sometimes (i guess when the file already existed) returns a *.k_1.zip. KNOSSOS doesn’t correct it so the file is submitted with the same extension resulting in an expat error.

[Optiligence]

I tried to clear this up a bit. Richard was starting a new task and the initial file had an incorrect extension.