ostree: Always substitute basearch

When ref is not modified via pungi config, we read it from the treefile
and substitute in basearch.

When pungi is configured to replace it, it modifies the treefile and
then used the value from config to avoid parsing the file. This however
did not substitute the basearch value.

We can simply use one code path for getting the value. This will work
for both cases.

Fixes: https://pagure.io/pungi/issue/866
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/ostree/tree.py

@@ -61,11 +61,7 @@ class Tree(OSTree):
         if not tag_ref:
             print('Not updating ref as configured')
             return
-        # if ostree_ref argument is given, it overrides ref value from treefile
-        if self.ostree_ref:
-            ref = self.ostree_ref
-        else:
-            ref = get_ref_from_treefile(self.treefile)
+        ref = get_ref_from_treefile(self.treefile)
         commitid = get_commitid_from_commitid_file(self.commitid_file)
         print('Ref: %r, Commit ID: %r' % (ref, commitid))
         if ref and commitid: