test_yum_package_downloading.py: Don't hardcode a value for EOPNOTSUPP

For historical reasons, errno numbers are not the same on all
architectures (compatibility with other operating systems already
available on the same hardware was considered more important than
having the same numbers on all Linux architectures).

tests/python/tests/test_yum_package_downloading.py

@@ -6,6 +6,7 @@
 import unittest
 import tempfile
 import xattr
+import errno
 
 import tests.servermock.yum_mock.config as config
 
@@ -758,7 +759,7 @@ def test_download_packages_with_resume_02(self):
                            "user.librepo.downloadinprogress".encode("utf-8"),
                            "".encode("utf-8"))
         except IOError as err:
-            if err.errno == 95:
+            if err.errno == errno.EOPNOTSUPP:
                 self.skipTest('extended attributes are not supported')
             raise