run compress plugin after pulp_push

Now that pulp_push is smart enough to strip layers from the tarball,
it is more efficient to let it do that manipulation before the
tarball we'll upload to Koji is compressed.

This saves a round of decompression.

inputs/prod_inner.json

@@ -79,13 +79,6 @@
     }
   ],
   "postbuild_plugins": [
-    {
-      "name": "compress",
-      "args": {
-        "load_exported_image": true,
-        "method": "gzip"
-      }
-    },
     {
       "name": "tag_by_labels"
     },
@@ -113,6 +106,13 @@
         "dockpulp_loglevel": "INFO"
       }
     },
+    {
+      "name": "compress",
+      "args": {
+        "load_exported_image": true,
+        "method": "gzip"
+      }
+    },
     {
       "args": {
         "image_id": "BUILT_IMAGE_ID"