Use -- to treat filenames as non-option args to gpg.

Ordinarily I'd also check that the filename was not "-", or perhaps
get the absolute path, but in this case I know the filename. (Otherwise
this could result in a hung process as gpg waited for stdin.)

leiningen-core/src/leiningen/core/user.clj

@@ -79,7 +79,7 @@
      (let [{:keys [out err exit]} (try (shell/sh
                                         (gpg-program)
                                         "--quiet" "--batch"
-                                        "--decrypt" (str file))
+                                        "--decrypt" "--" (str file))
                                        (catch java.io.IOException e
                                          {:exit 1 :err (.getMessage e)}))]
        (if (pos? exit)