Get repofile directories from dnf config, do not search subdirectories

yum/dnf does not look into subdirectories, so leapp should not do that
either to avoid reporting false positives.

repos/system_upgrade/el7toel8/libraries/repofileutils.py

@@ -1,8 +1,15 @@
 import json
+import os
 
 from leapp.libraries.common import mounting, utils
+from leapp.libraries.stdlib import api
 from leapp.models import RepositoryFile, RepositoryData, fields
 
+try:
+    import dnf
+except ImportError:
+    api.current_logger().warn('repofileutils.py: failed to import dnf')
+
 
 def _parse_repository(repoid, repo_data):
     def asbool(x):
@@ -35,12 +42,26 @@ def parse_repofile(repofile):
     return RepositoryFile(file=repofile, data=data)
 
 
+def get_repodirs():
+    """
+    Return all directories yum scans for repository files, if they exist.
+    By default, the possible paths on RHEL 7 should be:
+    ['/etc/yum.repos.d', '/etc/yum/repos.d', '/etc/distro.repos.d']
+
+    ATTENTION: Requires the dnf module to be present.
+    TODO: Get repodirs inside given context.
+    """
+    with dnf.base.Base() as base:
+        base.conf.read(priority=dnf.conf.PRIO_MAINCONFIG)
+        return list({os.path.realpath(d) for d in base.conf.reposdir if os.path.isdir(d)})
+
+
 def get_parsed_repofiles(context=mounting.NotIsolatedActions(base_dir='/')):
     """
     Scan all repositories on the system.
 
-    Repositories are scanned under /etc/yum.repos.d/ of the given context.
-    By default the context is the host system.
+    Repositories are scanned under repository directories (as reported by dnf)
+    of the given context. By default the context is the host system.
 
     ATTENTION: Do not forget to ensure the redhat.repo file is regenerated
     by RHSM when used.
@@ -50,7 +71,7 @@ def get_parsed_repofiles(context=mounting.NotIsolatedActions(base_dir='/')):
     :rtype: List(RepositoryFile)
     """
     repofiles = []
-    cmd = ['find', '/etc/yum.repos.d/', '-type', 'f', '-name', '*.repo']
+    cmd = ['find', '-L'] + get_repodirs() + ['-maxdepth', '1', '-type', 'f', '-name', '*.repo']
     repofiles_paths = context.call(cmd, split=True)['stdout']
     for repofile_path in repofiles_paths:
         repofile = parse_repofile(context.full_path(repofile_path))