Fix double-escaping of path segments on 1.6.1+

As of:

https://github.com/openSUSE/osc/commit/3f14cef53a853296d7f60bf7b14eb86615842cf9



`osc.core.makeurl` will escape path comonents itself, so calling
`pathname2url` ends up double-escaping, resulting in 404 errors with
filenames that have special characters.

Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>

osc_plugin_dput/main.py

@@ -192,13 +192,18 @@ def do_dput(self, subcmd, opts, *args):
         superseded = set()
         retained = set()
 
+        # osc <1.6.1 doesn't automatically escape path members.
+        should_escape_filename = osc.core.makeurl('', ['+']) == '/+'
+
         for f in remote_file_list.keys():
             if f.endswith('.dsc'):
                 u = osc.core.makeurl(conf.config['apiurl'],
                                      ['source',
                                       proj_name,
                                       package_name,
-                                      pathname2url(f)],
+                                      pathname2url(f)
+                                        if should_escape_filename
+                                        else f],
                                      query={})
 
                 remote_dsc = Dsc(osc.core.streamfile(u, bufsize='line'))