make sure to use the correct out_file

When installing more than one package, the out_file is not correct when doing
the install.

salt/spm/__init__.py

@@ -359,6 +359,7 @@ class SPMClient(object):
 
         # First we download everything, then we install
         for package in dl_list:
+            out_file = dl_list[package]['dest_file']
             # Kick off the install
             self._install_indv_pkg(package, out_file)
         return