Only use repos with valid urls for test_server.py

libdnf-0.22.5-5 changed something and now the repos with fake urls are
failing when loaded by test_server.py (they still work fine with
test_projects.py) so only use the 'good' repos with the test_server.py
tests -- the others weren't needed for any of its tests anyway.

Related: rhbz#1678937

tests/pylorax/test_server.py

@@ -103,9 +103,9 @@ class ServerTestCase(unittest.TestCase):
 
         make_dnf_dirs(server.config["COMPOSER_CFG"])
 
-        # copy over the test dnf repositories
+        # copy over the test_server dnf repositories
         dnf_repo_dir = server.config["COMPOSER_CFG"].get("composer", "repo_dir")
-        for f in glob("./tests/pylorax/repos/*.repo"):
+        for f in glob("./tests/pylorax/repos/server-*.repo"):
             shutil.copy2(f, dnf_repo_dir)
 
         # Modify fedora vs. rawhide tests when running on rawhide