:else for conditions: remove condp (won't work)

`condp` can't usually take an :else label for its default since it's rare that the predicate would happen to evaluate to `true` for :else --- as demonstrated by the next example which uses condp with an unlabelled default.

Author: zw

README.md

@@ -569,7 +569,7 @@ pairwise constructs as found in e.g. `let` and `cond`.
  (.. System getProperties (get "os.name"))
  ```
 
-* Use `:else` as the catch-all test expression in `cond` and `condp`.
+* Use `:else` as the catch-all test expression in `cond`.
 
  ```Clojure
  ;; good