zypper_repository: Fix repo parsing for empty list

When no repositories are defined in zypper, the return code
of "zypper repos" is 6. Handle that case and don't fail
if zypper_repository has to deal with an empty repo list.

Fixes https://github.com/ansible/ansible-modules-extras/issues/795

lib/ansible/modules/extras/packaging/os/zypper_repository.py

@@ -95,10 +95,10 @@ def zypper_version(module):
 def _parse_repos(module):
     """parses the output of zypper -x lr and returns a parse repo dictionary"""
     cmd = ['/usr/bin/zypper', '-x', 'lr']
-    repos = []
-
     from xml.dom.minidom import parseString as parseXML
-    rc, stdout, stderr = module.run_command(cmd, check_rc=True)
+    rc, stdout, stderr = module.run_command(cmd, check_rc=False)
+    if rc == 0:
+        repos = []
         dom = parseXML(stdout)
         repo_list = dom.getElementsByTagName('repo')
         for repo in repo_list:
@@ -108,8 +108,17 @@ def _parse_repos(module):
             opts['url'] = repo.getElementsByTagName('url')[0].firstChild.data
             # A repo can be uniquely identified by an alias + url
             repos.append(opts)
-
         return repos
+    # exit code 6 is ZYPPER_EXIT_NO_REPOS (no repositories defined)
+    elif rc == 6:
+        return []
+    else:
+        d = { 'zypper_exit_code': rc }
+        if stderr:
+            d['stderr'] = stderr
+        if stdout:
+            d['stdout'] = stdout
+        module.fail_json(msg='Failed to execute "%s"' % " ".join(cmd), **d)
 
 def _parse_repos_old(module):
     """parses the output of zypper sl and returns a parse repo dictionary"""