Always clear offline updates file after a repair operation

No matter what the results of the repair operation were, there's nothing
of any value that anyone can do with the file anymore, and if it sticks
around, it can annoy the user on every subsequent login for no good
reason. So let's just remove it.

BUG: 451753
BUG: 450973
CCBUG: 467638
FIXED-IN: 5.27.5