utf8 mystery in pp_index

I had a new Coverity run on blead and it noticed an oddity in 
pp.c:pp_index:3551 or thereabouts:

3550            sv_utf8_upgrade(temp);

     	const: At condition little_utf8, the value of little_utf8 must be 
equal to 0.
     	dead_error_condition: The condition little_utf8 cannot be true.

3551            if (little_utf8) {
     	
CID 152145 (#1 of 1): Logically dead code (DEADCODE)
dead_error_begin: Execution cannot reach this statement: big = temp;.

3552                big = temp;

And indeed, the whole "if (little_utf8) {" is in the else branch
of an earlier "if (little_utf8) {" and nothing in the else branch
seems to be capable of modifying the little_utf8 (unlike in the true
branch where bytes_from_utf8() call can modify the little_utf8).

• utf8 mystery in pp_index by Jarkko Hietaniemi
• Re: utf8 mystery in pp_index by Aristotle Pagaltzis