CLJCLR-127: fix slurp argument warning

Author: dmiller

Clojure/Clojure.Source/clojure/core.clj

@@ -7009,7 +7009,7 @@ clojure.lang.IKVReduce
 
 (defn- normalize-slurp-opts
   [opts]
-  (if (not (keyword? (first opts)))                                              ;;; (string? (first opts))
+  (if (string? (first opts))
     (do
       (println "WARNING: (slurp f enc) is deprecated, use (slurp f :encoding enc).")
       [:encoding (first opts)])

Clojure/Clojure.Tests/clojure/test_clojure/clr/io.clj

@@ -61,7 +61,7 @@
         (is (=
               (platform-newlines "WARNING: (slurp f enc) is deprecated, use (slurp f :encoding enc).\n")
               (with-out-str
-                (is (= content (slurp f utf16))))))))))
+                (is (= content (slurp f "utf-16"))))))))))
 
 (deftest test-streams-defaults
   (let [f (temp-file "test-reader-writer")