[PATCH 4 of 6] graphlog: remove redundant check for empty revs

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1508680356 -32400
#      Sun Oct 22 22:52:36 2017 +0900
# Node ID 759d00588ebec2f0b9f6c6a762a7ba970e0f8d26
# Parent  731765e1876ba38dae45b53a5aed2c204f8c03d5
graphlog: remove redundant check for empty revs

diff --git a/mercurial/graphmod.py b/mercurial/graphmod.py
--- a/mercurial/graphmod.py
+++ b/mercurial/graphmod.py
@@ -48,9 +48,6 @@ def dagwalker(repo, revs):
     returned.
 
     """
-    if not revs:
-        return
-
     gpcache = {}
 
     for rev in revs: