Make subliminal always mangle cache keys to prevent long filenames

* Use dogpile.cache sha1_mangle_key to mangle cache keys

When using the subtitle hashes as cache keys, sometimes they come
out as filenames of 270 characters.
Not a lot of filesystems out there support filenames with over 250
characters.
This behaviour was reported with ext4 and zfs on both linux and FreeBSD.

The dogpile.cache utils come with a function that returns a hex digest
of the key, limiting the filename to a fixed length of 40 characters.

* Set region to subliminal.region and only then configure it, instead of assigning the result of configure to the property

* Make sure subliminal ALWAYS mangles keys with the sha1 to prevent filenames that are too long

bazarr/init.py

@@ -11,9 +11,7 @@ from get_args import args
 from logger import configure_logging
 from helper import path_mappings
 
-from dogpile.cache import make_region
 from dogpile.cache.region import register_backend as register_cache_backend
-from dogpile.cache.util import sha1_mangle_key
 import subliminal
 import datetime
 
@@ -116,10 +114,7 @@ db_upgrade()
 
 # Configure dogpile file caching for Subliminal request
 register_cache_backend("subzero.cache.file", "subzero.cache_backends.file", "SZFileBackend")
-
-subliminal.region = make_region(
-    key_mangler=sha1_mangle_key
-).configure(
+subliminal.region.configure(
     'subzero.cache.file',
     expiration_time=datetime.timedelta(days=30),
     arguments={'appname': "sz_cache", 'app_cache_dir': args.config_dir}

libs/subliminal/cache.py

@@ -3,6 +3,7 @@ from __future__ import absolute_import
 import datetime
 
 from dogpile.cache import make_region
+from dogpile.cache.util import sha1_mangle_key
 
 #: Expiration time for show caching
 SHOW_EXPIRATION_TIME = datetime.timedelta(weeks=3).total_seconds()
@@ -13,5 +14,5 @@ EPISODE_EXPIRATION_TIME = datetime.timedelta(days=3).total_seconds()
 #: Expiration time for scraper searches
 REFINER_EXPIRATION_TIME = datetime.timedelta(weeks=1).total_seconds()
 
-
-region = make_region()
+# Mangle keys to prevent long filenames
+region = make_region(key_mangler=sha1_mangle_key)