Controller is now a function fixture instead of a session.
requested to merge fix/MIP-649/test-merge-tabels-py-test-incompatible-schemas-merge-skipped into master
Created by: KFilippopolitis
The main problem on the issue is that on the controller fixture we had node addresses for all nodes. Once we tried to run the test they will most of the time reach to the problem that some nodes are unreachable and the controller will wait until their requests timeout. So now the controller fixture has only the address for global and localnode1.