Fix issue with ParamsProcessor

In free version, where there is no NSFileRepo extension, this would fail.
Make it more stable
However, i would like to see this whole mechanism improved. Currently, using the hook,
we can only override params processor, not add multiple processors, each of which may
add its own UI, or some processing. Registry would fit better here

[4.2.x]

ERM 29742

Change-Id: I9963f2d2771452f7f6318449fba55319bb3bbe2f
(cherry picked from commit c6f68a1df630f63e367af5d32e0b27b1f6a954ac)