fix old errors.New(fmt.Sprintf) usage
fix old errors.New(fmt.Sprintf) usage

Golint has warned:
should replace errors.New(fmt.Sprintf(...)) with fmt.Errorf(...) (golint)
and this patch does the simply fixup for that.

Signed-off-by: Tim Pepper <4807564e5a18784afafcf20dbdb5591e844b9075@vmware.com>

u-root/u-root,hugelgupf/u-root,GanShun/u-root,rminnich/u-root,u-root/u-root,hugelgupf/u-root,GanShun/u-root,rminnich/u-root,rminnich/u-root,u-root/u-root,hugelgupf/u-root,GanShun/u-root,rminnich/u-root,hugelgupf/u-root