[Nepomuk] DataManagementModel protected types

[Vishesh Handa]

Hey Sebastian

I just made a patch to remove the 
DataManagementModel::containsResourceWithProtectedType function. This function 
is a little slow and in my benchmarks it takes about 8% of the total execution 
time.

The only reason this is there is to make sure clients do not add or modify 
classes, properties or graphs through the DataManagement APIs. But I don't 
think it is worth the 8% penalty.

Nowadays we have a pretty good view of who all is using Nepomuk and we can 
control what they are doing.

Any comments?

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Vishesh Handa