manifest_xml: support nested submanifests

Change-Id: I58f91c6b0db631bb7f55164f41d11d3a349ac94f
Signed-off-by: Guillaume Micouin-Jorda <gmicouin@netcourrier.com>
Signed-off-by: Hadamik Stephan <Stephan.Hadamik@continental-corporation.com>
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/392020
Reviewed-by: Ben PUJOL <pujolbe@gmail.com>
Reviewed-by: LaMont Jones <lamontjones@google.com>
Tested-by: Roberto Prado <roberto.prado.c@gmail.com>
Commit-Queue: Roberto Prado <roberto.prado.c@gmail.com>
Tested-by: LaMont Jones <lamontjones@google.com>
Reviewed-by: Roberto Prado <roberto.prado.c@gmail.com>
diff --git a/manifest_xml.py b/manifest_xml.py
index b27bf80..edbebaa 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -305,7 +305,7 @@
             parent.repodir,
             linkFile,
             parent_groups=",".join(groups) or "",
-            submanifest_path=self.relpath,
+            submanifest_path=os.path.join(parent.path_prefix, self.relpath),
             outer_client=outer_client,
             default_groups=default_groups,
         )