Call the _ method from i18n.py

Gettext can sometimes return bytes which needs to be converted and this
is handled in the i18n.py source file.

This should fix broken Rawhide builds.

pykickstart/commands/reqpart.py

@@ -22,9 +22,7 @@
 from pykickstart.errors import KickstartParseError, formatErrorMsg
 from pykickstart.options import KSOptionParser
 
-import gettext
-# typeshed is missing the stub for ldgettext
-_ = lambda x: gettext.ldgettext("pykickstart", x)
+from pykickstart.i18n import _
 
 class F23_ReqPart(KickstartCommand):
     removedKeywords = KickstartCommand.removedKeywords