kojiwrapper: Deal with multiple values for image-build

When the config for image-build command contains multiple values, they
should be joined with commas into a single value.

Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/wrappers/kojiwrapper.py

@@ -171,6 +171,8 @@ class KojiWrapper(object):
         for section, opts in config_options.items():
             cfg_parser.add_section(section)
             for option, value in opts.items():
+                if isinstance(value, list):
+                    value = ','.join(value)
                 if not isinstance(value, six.string_types):
                     # Python 3 configparser will reject non-string values.
                     value = str(value)

tests/test_koji_wrapper.py

@@ -78,7 +78,7 @@ class KojiWrapperTest(KojiWrapperBaseTestCase):
                     'target': 'test-target',
                     'install_tree': '/tmp/test/install_tree',
                     'arches': 'x86_64',
-                    'format': 'docker,qcow2',
+                    'format': ['docker', 'qcow2'],
                     'kickstart': 'test-kickstart',
                     'ksurl': 'git://example.com/ks.git',
                     'distro': 'test-distro',