Split functionality of setting delete_moves_to_trash

Before it would handle two scenarios:
1) When a file is deleted
2) When a file has been modified

Scenario 2 now has it's own configuration called modified_moves_to_trash

DEBIAN/Makefile was trying to remove a file called greyhole-mv which does not exist causing the script to fail, have commented out until gboudreau adds that script into the repo.