Removed redundant max() call.

Change suggested by Nick Coghlan.
diff --git a/Lib/io.py b/Lib/io.py
index d85ed49..d5c8dfe 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -833,7 +833,7 @@
         if whence == 0:
             if pos < 0:
                 raise ValueError("negative seek position %r" % (pos,))
-            self._pos = max(0, pos)
+            self._pos = pos
         elif whence == 1:
             self._pos = max(0, self._pos + pos)
         elif whence == 2: