convert/svn: support more OS specific auth providers via svn 1.6 API

hgext/convert/transport.py

@@ -44,6 +44,16 b' def _create_auth_baton(pool):'
         svn.client.get_ssl_server_trust_file_provider(pool),
         ]
     # Platform-dependant authentication methods
+    getprovider = getattr(svn.core, 'svn_auth_get_platform_specific_provider',
+                          None)
+    if getprovider:
+        # Available in svn >= 1.6
+        for name in ('gnome_keyring', 'keychain', 'kwallet', 'windows'):
+            for type in ('simple', 'ssl_client_cert_pw', 'ssl_server_trust'):
+                p = getprovider(name, type, pool)
+                if p:
+                    providers.append(p)
+    else:
     if hasattr(svn.client, 'get_windows_simple_provider'):
         providers.append(svn.client.get_windows_simple_provider(pool))