music: do not transfer cache db

Do not transfer the cache db between devices, drop it instead.

This is at best useless (timestamps and ids will be invalid) and at
worst actively detrimental (timestamps and ids are similar), so
better to reindex than try to read from the cache.

Resolves #467.

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## dev
+
+#### What's Fixed
+- Disc number is no longer mis-aligned when no subtitle is present
+
 ## 3.1.1
 
 #### What's New

app/src/main/AndroidManifest.xml

@@ -24,12 +24,12 @@
         android:name=".Auxio"
         android:allowBackup="true"
         android:fullBackupContent="@xml/backup_descriptor"
+        android:dataExtractionRules="@xml/data_extraction_rules"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/info_app_name"
         android:roundIcon="@mipmap/ic_launcher"
         android:supportsRtl="true"
         android:theme="@style/Theme.Auxio.App"
-        android:dataExtractionRules="@xml/data_extraction_rules"
         android:appCategory="audio"
         android:enableOnBackInvokedCallback="true"
         tools:ignore="UnusedAttribute">

app/src/main/res/xml/backup_descriptor.xml

@@ -1,2 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<full-backup-content />
+<full-backup-content>
+    <!-- Cache databases are useless between devices, drop them -->
+    <exclude domain="database" path="music_cache.db" />
+</full-backup-content>

app/src/main/res/xml/data_extraction_rules.xml

@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <data-extraction-rules>
-    <cloud-backup />
-    <device-transfer />
+    <!-- Cache databases are useless between devices, drop them -->
+    <cloud-backup>
+        <exclude domain="database" path="music_cache.db" />
+    </cloud-backup>
+    <device-transfer>
+        <exclude domain="database" path="music_cache.db" />
+    </device-transfer>
 </data-extraction-rules>