I try to change file emblems (file attributes of type STRINGV), using Gio.
All attempts to use the STRINGV type either are explicitly refused or segfault. 



1. Neither Gio.File.set_attribute() nor Gio.FileInfo.set_attribute() accepts STRINGV arguments.


```
>>> from gi.repository import Gio
>>> Gio._version
'2.0'
>>> f = Gio.File.new_for_path('test')
>>> f.set_attribute("metadata::emblems",
      Gio.FileAttributeType.STRINGV,
      ["folder_emblem_in_progress"],
      Gio.FileQueryInfoFlags(0),
      None)
ValueError: Pointer arguments are restricted to integers, capsules, and None. See: https://bugzilla.gnome.org/show_bug.cgi?id=683599



2. Gio.FileInfo.set_attribute_stringv() segfault.


>>> from gi.repository import Gio
>>> fi = Gio.FileInfo()
>>> fi.set_attribute_stringv("metadata::emblems", ["folder_emblem_in_progress"])
[1]    21457 segmentation fault (core dumped)  python



Note that it worked with the old Gio binding:

>>> import gio
>>> 
>>> f = gio.File(file_path)
>>> f.set_attribute("metadata::emblems",
                               gio.FILE_ATTRIBUTE_TYPE_STRINGV,
                               ["folder_emblem_in_progress"])