Minor fix for empty logarithmic chart

CHANGELOG

@@ -1,5 +1,8 @@
-V 1.5.1 - UNRELEASED
+V 1.5.2 - UNRELEASED
+
+V 1.5.1
 	Add `stack_from_top` option to reverse stack graph data order
+	Minor fix for empty logarithmic chart
 
 V 1.5.0
 	Add per serie configuration

pygal/__init__.py

@@ -21,7 +21,7 @@ Pygal -  A python svg graph plotting library
 
 """
 
-__version__ = '1.5.0'
+__version__ = '1.5.1'
 import sys
 from pygal.config import Config
 from pygal.ghost import Ghost, REAL_CHARTS

pygal/graph/base.py

@@ -65,7 +65,7 @@ class BaseGraph(object):
                 [get(val)
                  for serie in self.series for val in serie.safe_values]))
 
-            self.zero = min(positive_values or 1,) or 1
+            self.zero = min(positive_values or (1,)) or 1
         self._draw()
         self.svg.pre_render()