I suppose I should add a test for this.

I just added a test that --sigs-needed 1000 works on signed content-addressed paths.

Actually we can just stop verifying sigs when we know that it's a content-addressable path, i.e. change

if (info2->isContentAddressed(*store)) validSigs = ValidPathInfo::maxSigs;
doSigs(info2->sigs);

to

if (info2->isContentAddressed(*store)) 
  validSigs = ValidPathInfo::maxSigs;
else
  doSigs(info2->sigs);

@edolstra I considered adding || info->isContentAddressed(*store) to this if statement:

But I figured there might be a reason that we also ask substituters whether their info is content addressed. Like maybe somehow someone's metadata is screwed up and dropped the fact that the path is content addressed.

@edolstra Is that reason to keep the changes as is, or would you rather just call the path good if it's content-addressed?

@edolstra ping.