Remove outdated versionchanged entry

mdickinson · mdickinson · commit 4035aace1adb · 2009-10-01T20:11:11.000Z
diff --git a/Doc/library/cmath.rst b/Doc/library/cmath.rst
@@ -94,9 +94,6 @@ Power and logarithmic functions
    specified, returns the natural logarithm of *x*. There is one branch cut, from 0
    along the negative real axis to -∞, continuous from above.
 
-   .. versionchanged:: 2.4
-      *base* argument added.
-
 
 .. function:: log10(x)
 
