annotate: remove redundant check for empty list of annotation data

It isn't necessary because zip(*pieces) returns [] if pieces are empty,
and pieces are empty only if lines are empty.

mercurial/commands.py

@@ -323,7 +323,6 b' def annotate(ui, repo, *pats, **opts):'
                 pieces.append(["%s%s%s" % (sep, ' ' * (ml - w), x)
                                for x, w in sized])
 
-        if pieces:
             for p, l in zip(zip(*pieces), lines):
                 ui.write("%s: %s" % ("".join(p), l[1]))