opkg: Use a curl backend instead of busybox's wget which can sometimes have problem with http redirections for instance

0001-Allow-adbd-to-be-ran-as-root.patch contains paths with 'a/', 'b/' prefixes which need to be stripped.

```
Applying patch 0001-Allow-adbd-to-be-ran-as-root.patch
can't find file to patch at input line 14
Perhaps you used the wrong -p or --strip option?
```