Bug/dbname concatenated during func tests

### Description
Added the function 'dbDrop' to harnessFunctions.sh and calling the function to cleanup databases after use in the functests,
What I really was trying to do was to catch the 'ftest-ftest-ftest ...' error but it seems to have disappeared by itself. With this cleanup the functional tests no longer fail 'sponteanously', which is good, but the bug might still be out there. To try to catch the bug (some day), I have left 6 LM_Ms in the code to give us clues in case it ever happens again.
Now, I am aware it is not a good idea to leave this 'dirt' in the code, I just see no other alternative if we want to catch this bug.

Defered to issue https://github.com/telefonicaid/fiware-orion/issues/651