Delete a tag from the node.

async def delTag(self, tag, init=False):
        '''
        Delete a tag from the node.
        '''
        path = s_chop.tagpath(tag)

        name = '.'.join(path)

        if self.isrunt:
            raise s_exc.IsRuntForm(mesg='Cannot delete tags from runt nodes.',
                                   form=self.form.full, tag=tag)

        curv = self.tags.pop(name, s_common.novalu)
        if curv is s_common.novalu:
            return False

        pref = name + '.'

        subtags = [(len(t), t) for t in self.tags.keys() if t.startswith(pref)]
        subtags.sort(reverse=True)

        removed = []

        for sublen, subtag in subtags:
            valu = self.tags.pop(subtag, None)
            removed.append((subtag, valu))

        removed.append((name, curv))

        info = {'univ': True}
        sops = [('prop:del', (self.buid, self.form.name, '#' + t, info)) for (t, v) in removed]

        # fire all the splices
        splices = [self.snap.splice('tag:del', ndef=self.ndef, tag=t, valu=v) for (t, v) in removed]
        await self.snap.stor(sops, splices)

        # fire all the handlers / triggers
        [await self.snap.core.runTagDel(self, t, v) for (t, v) in removed]