Remove unused dangling identifiers after while -> for loop rewrite

[elliottyoon]

pub unsafe fn insertion_sort(n: i32, p: *mut i32) {
    let mut i: i32 = 1 as i32; // Remove this.
    for i in 1..n {
        let tmp: i32 = *p.offset(i as isize);
        let mut j: i32 = i;
        while j > 0 as i32 && *p.offset((j - 1 as i32) as isize) > tmp {
            *p.offset(j as isize) = *p.offset((j - 1 as i32) as isize);
            j -= 1;
        }
        *p.offset(j as isize) = tmp;
    }
}