Every time the "Important" flag of an email is removed nepomuk does not remove the association between the email and the "Important" tag from its database.

Reproducible: Always

Steps to Reproduce:
1. Mark a message as important
2. Remove the important flag again
Actual Results:  
Open akonadiconsole, search for the email and have a look at the "Nepomuk" tab: 
"Important" is still checked although the \FLAGGED flag ("Internals" tab) is not set anymore.

Expected Results:  
"Important" should not be a tag of the email anymore.

I had a look at the code:
For every update of an email the nepomuk feeder agent creates a new graph which is merged into the old already saved graph of the same email. The newly created graph correctly does not contain the association with the tag but the old graph does, of course. Nepomuk2::storeRessources() is used to push and merge the new graph into the old one but that function does not remove the tag association because from its point of view the association should not be deleted because only new information of the new graph should be added to the old graph.
At least that's what I understood.
I am not sure how to fix this therefore I wrote this bug report.