library: Remove dead branch in file2strvec

library: Remove dead branch in file2strvec

A while loop used n >=0
A branch inside the loop had a test for n<0
That's never going to happen!
So the branch must go. There is similiar code outside
the branch. Yes, I miss pythons while else here.

Also cleaned up the ***-awful indentation this function had.
No wonder that branch lived for so long there.

References:
 Coverity #99119

Signed-off-by: Craig Small <csmall@dropbear.xyz>