Remove repo_name warning

The repo name is considered missing if it is not comming from repo_name.
We can mark it as 'found' then and avoid a lot of warning.

BUG=None
TEST=./runtests
TEST=install portage with this patch -> no more warnings.

Change-Id: I323387353f03d01c27d67a3a9e65457cce257475
Reviewed-on: https://chromium-review.googlesource.com/216613
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/pym/portage/repository/config.py b/pym/portage/repository/config.py
index 5e0d055..24c3112 100644
--- a/pym/portage/repository/config.py
+++ b/pym/portage/repository/config.py
@@ -233,6 +233,7 @@
 				# useful when having two copies of the same repo enabled
 				# to avoid modifying profiles/repo_name in one of them
 				self.name = layout_data['repo-name']
+				self.missing_repo_name = False
 
 			for value in ('allow-missing-manifest',
 				'allow-provide-virtual', 'cache-formats',