pkg/uroot/bb: use recommended way of Go-quoting a string.
pkg/uroot/bb: use recommended way of Go-quoting a string.

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