superproject: Use bugurl from contactinfo in the missing commits error message.

+ In XmlManifest._Unload set 'bugurl' to Wrapper().BUG_URL.
+ contactinfo returns a namedtuple.
+ bug_url can be accessed as self._manifest.contactinfo.bugurl.

Tested the code with the following commands.

$ ./run_tests -v

Added contactinfo tag to default.xml and verified that bugurl is used.

Bug: [google internal] b/186220520.
Change-Id: Iaafd6465e072b2e47a0a0b548bf6cb608a0b0a04
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/306342
Tested-by: Raman Tenneti <rtenneti@google.com>
Reviewed-by: Mike Frysinger <vapier@google.com>

git_superproject.py

@@ -28,7 +28,6 @@ import sys
 
 from git_command import GitCommand
 from git_refs import R_HEADS
-from wrapper import Wrapper
 
 _SUPERPROJECT_GIT_NAME = 'superproject.git'
 _SUPERPROJECT_MANIFEST_NAME = 'superproject_override.xml'
@@ -283,7 +282,7 @@ class Superproject(object):
         projects_missing_commit_ids.append(path)
     if projects_missing_commit_ids:
       print('error: please file a bug using %s to report missing commit_ids for: %s' %
-            (Wrapper().BUG_URL, projects_missing_commit_ids), file=sys.stderr)
+            (self._manifest.contactinfo.bugurl, projects_missing_commit_ids), file=sys.stderr)
       return None
 
     manifest_path = self._WriteManfiestFile()