Revert "Change to avoid if statements."

This reverts commit 62f6934.

Author: drvinceknight

axelrod/random_.py

@@ -2,9 +2,6 @@
 import numpy
 from axelrod import Actions
 
-# A dictionary mapping 0 or 1 probability of cooperating to an action.
-choices = {0: Actions.D, 1: Actions.C}
-
 
 def random_choice(p=0.5):
     """
@@ -23,11 +20,16 @@ def random_choice(p=0.5):
     -------
     axelrod.Actions.C or axelrod.Actions.D
     """
-    try:
-        return choices[p]
-    except KeyError:
-        r = random.random()
-        return choices[r < p]
+    if p == 0:
+        return Actions.D
+
+    if p == 1:
+        return Actions.C
+
+    r = random.random()
+    if r < p:
+        return Actions.C
+    return Actions.D
 
 
 def randrange(a, b):