Correct duplicate symlink check in TCZ
Correct duplicate symlink check in TCZ

This commit corrects the way TCZ looks for duplicate symlinks when
it is creating symlinks from fetched pacakges. Before, the command
would abort on symlinks that should exist. Now it will safely
ignore existing symlinks. Use correct go error handling.

Signed-off-by: laconicpneumonic <1ce3e34facf648ba6954bc9b0fae4ba758e448bd@gmail.com>

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