wsgi plugins: mod_wsgi expects bytes as an output

python3-mod_wsgi expects that the application() method returns
bytes otherwise it breaks.

https://pagure.io/freeipa/issue/4985

Reviewed-By: Martin Basti <mbasti@redhat.com>

.travis.yml

@@ -66,6 +66,7 @@ env:
           TEST_RUNNER_CONFIG=".test_runner_config_py3_temp.yaml"
           TESTS_TO_RUN="test_cmdline
                 test_ipalib
+                test_ipaserver/test_changepw.py
                 test_pkcs10
                 test_xmlrpc/test_location_plugin.py
                 test_xmlrpc/test_nesting.py
@@ -98,7 +99,6 @@ env:
             # test_ipapython/test_kerberos.py
             # test_ipapython/test_ssh.py
             # test_ipaserver/httptest.py
-            # test_ipaserver/test_changepw.py
             # test_ipaserver/test_dnssec.py
             # test_ipaserver/test_install/test_adtrustinstance.py
             # test_ipaserver/test_install/test_service.py

install/wsgi/plugins.py

@@ -34,10 +34,12 @@ def get_plugin_index():
     index = 'define([],function(){return['
     index += ','.join("'"+x+"'" for x in dirs)
     index += '];});'
-    return index
+    return index.encode('utf-8')
 
 def get_failed():
-    return 'define([],function(){return[];});/*error occured: serving default */'
+    return (
+        b'define([],function(){return[];});/*error occured: serving default */'
+    )
 
 def application(environ, start_response):
     try:

ipaserver/rpcserver.py

@@ -650,7 +650,7 @@ class KerberosSession(HTTP_Status):
         headers.append(('IPASESSION', session_cookie))
 
         start_response(HTTP_STATUS_SUCCESS, headers)
-        return ['']
+        return [b'']
 
 
 class KerberosWSGIExecutioner(WSGIExecutioner, KerberosSession):
@@ -1090,7 +1090,7 @@ class change_password(Backend, HTTP_Status):
         start_response(status, response_headers)
         output = _success_template % dict(title=str(title),
                                           message=str(message))
-        return [output]
+        return [output.encode('utf-8')]
 
 class sync_token(Backend, HTTP_Status):
     content_type = 'text/plain'
@@ -1188,7 +1188,7 @@ class sync_token(Backend, HTTP_Status):
         start_response(status, response_headers)
         output = _success_template % dict(title=str(title),
                                           message=str(message))
-        return [output]
+        return [output.encode('utf-8')]
 
 class xmlserver_session(xmlserver, KerberosSession):
     """