This commit essentially removes the step of backing up the databases as part of an upgrade. There are concerns that this may take a long time or eat up lots of resources in cases where there is alot of data. Also if the data is important it is likely that there will be a separate backup strategy for this.
Since it might be nice to offer to do this as an optional step in the future, I have not removed the code altogether but rather surrounded the backup invocation code with a conditional that is always false right now. When we can resolve where in the GUI to offer such a checkbox for managing the value of this value there will be no change necessary to the Upgrader class.