vector subscript out of range when call buildPyramid() (Bug #2975)

void foo(cv::Mat1f sigma) {
cv::vector<cv::Mat1f> gs;
cv::buildPyramid(sigma, gs, 5);
}

will cause vector subscript out of range exception.

in matrix.cpp, this function
void _OutputArray::create(int dims, const int* sizes, int mtype, int i, bool allowTransposed, int fixedDepthMask) const,
...
CV_Assert( k STD_VECTOR_MAT );
//if( k STD_VECTOR_MAT ) {
vector<Mat>& v = (vector<Mat>)obj;

if( i < 0 )
{
            CV_Assert( dims  2 && (sizes[0]  1 || sizes[1]  1 || sizes[0]*sizes[1]  0) );
            size_t len = sizes[0]*sizes[1] > 0 ? sizes[0] + sizes[1] - 1 : 0, len0 = v.size();

CV_Assert(!fixedSize() || len == len0);
            v.resize(len);
            if( fixedType() )
{
                int _type = CV_MAT_TYPE(flags);
                for( size_t j = len0; j < len; j++ )
    {
                    if( v[i].type() == _type )
                        continue;
                    CV_Assert( v[i].empty() );
                    v[i].flags = (v[i].flags & ~CV_MAT_TYPE_MASK) | _type;
                }
            }
            return;
        }
Inside the loop, loop iterator is j but v[i] was used. And i must be less than 0. And that caused the exception. Should change all v[i] to v[j] in this block.