animation conversion: add in_variation to list of variables defined at start as False

All of these variables are again defined as False when [unit] is in the line, but in_variation was missing from this earlier list. This caused wmllint to crash with an UnboundLocalError on a page of (UtBS) Kaleh-style macros that had no [unit] tag.

data/tools/wmllint

@@ -1067,7 +1067,7 @@ def hack_syntax(filename, lines):
                 self.attackend = None
             def __repr__(self):
                 return `self.__dict__`
-        in_attack = in_animation = in_female = False
+        in_attack = in_animation = in_female = in_variation = False
         animations = []
         attackname = None
         attackline = None