Run case sensitivity check (#1586) on bytestring

This should avoid problems when querying for Unicode paths.

Author: sampsyo

beets/library.py

@@ -64,7 +64,8 @@ def __init__(self, field, pattern, fast=True, case_sensitive=None):
         # By default, the case sensitivity depends on the filesystem
         # that the query path is located on.
         if case_sensitive is None:
-            case_sensitive = beets.util.case_sensitive(pattern)
+            path = util.bytestring_path(util.normpath(pattern))
+            case_sensitive = beets.util.case_sensitive(path)
         self.case_sensitive = case_sensitive
 
         # Use a normalized-case pattern for case-insensitive matches.