convert: playlist: Use normpath for playlist file

Fixes FileNotFoundError when for example a tilde (~) characteris used for a
--dest path.

beets/util/m3u.py

@@ -15,7 +15,7 @@
 """Provides utilities to read, write an manipulate m3u playlist files."""
 
 
-from beets.util import syspath
+from beets.util import syspath, normpath
 
 
 class EmptyPlaylistError(Exception):
@@ -70,6 +70,6 @@ class M3UFile():
         if not self.media_list:
             raise EmptyPlaylistError
         contents = header + self.media_list
-        with open(syspath(self.path), "w", encoding="utf-8") as playlist_file:
+        with open(syspath(normpath(self.path)), "w", encoding="utf-8") as playlist_file:
             playlist_file.writelines('\n'.join(contents))
             playlist_file.write('\n')  # Final linefeed to prevent noeol file.

beetsplug/convert.py

@@ -483,7 +483,8 @@ class ConvertPlugin(BeetsPlugin):
             # media file paths to be unicode. Additionally we use relative
             # paths to ensure readability of the playlist on remote
             # computers.
-            self._log.info("Creating playlist file: {0}", playlist)
+            self._log.info("Creating playlist file: {0}",
+                           util.normpath(playlist))
             items_paths = [
                 util.syspath(item.destination(
                     basedir=dest, path_formats=path_formats, fragment=True