pod2man: Fix for machines upgraded to Mavericks

Closes Homebrew/homebrew#24590.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Library/ENV/4.3/pod2man

 #!/bin/bash
-POD2MAN=$(/usr/bin/which pod2man5.12 || echo /usr/bin/pod2man)
+POD2MAN=$(/usr/bin/which pod2man5.16 || /usr/bin/which pod2man5.12 || echo /usr/bin/pod2man)
 exec $POD2MAN "$@"