fix bug caused by partial refactoring

Author: micha

boot/core/src/boot/core.clj

@@ -205,8 +205,8 @@
 (defn mktgtdir!
   "Create a tempdir managed by boot into which tasks can emit artifacts. See
   https://github.com/tailrecursion/boot#boot-managed-directories for more info."
-  [key & [name]]
-  (util/with-let [f (mktmpdir! key name)]
+  [key]
+  (util/with-let [f (mktmpdir! key)]
     (swap! tgtdirs conj f)
     (set-env! :src-paths #{(.getPath f)})
     (add-sync! (get-env :tgt-path) [(.getPath f)])))