Sliver compilation issue when using debug mode

[rkervella]

Generating a sliver in debug mode using the -d or --debug flag results in the following line being stripped out:
log.SetOutput(ioutil.Discard) - link
As this is the only usage of the ioutil lib in this package, the compiler complains about an unused import when generating in debug mode.

Implementing a dummy Discard writer to get rid of the import could be a solution.

[moloch--]

Fixed in master

[moloch--]

961c6e6#diff-69a1dc42a3adb051746de0c30cf7978bL11