Do not overwrite [illumina][run_summary]. Fixes #341

As the description says, this code should fix issue #341. I have been testing it on tools-dev with [this](http://tools-dev.scilifelab.se:5984/_utils/document.html?flowcells/6aaf23ed1f4b444c9704640f326971c2) flowcell document.

Before this change indeed the item [illumina][run_summary] was deleted. After this change the item is kept there. You can test it running ```pm qc upload-qc 131217_SN7001362_0105_BC3HTJACXX``` **on tools-dev.scilifelab.se**.