agetty: Remove superfluous fflush()

eval_issue_file() contains fflush(stdout). It comes from an old code that
used fputs() to write to the console.

In the new code, we write to a temporary memstream, and
fclose(ie->output) fully replaces possible fflush(ie->output) in this
implementation.

The new print_issue_file() does not need it as well, as it uses
unbuffered write_all().

Signed-off-by: Stanislav Brabec <sbrabec@suse.cz>

term-utils/agetty.c

@@ -1903,8 +1903,6 @@ static void eval_issue_file(struct issue *ie,
 			f = NULL;
 		} while (dirname);
 
-		fflush(stdout);
-
 		if ((op->flags & F_VCONSOLE) == 0)
 			ie->do_tcrestore = 1;
 	}