Merge branch 'dont-hardcode-account_type' into 'master-ose'

Don't hard-code accountType and use @string/account_type instead

See merge request bitfireAT/davdroid!12

app/src/main/res/xml/sync_calendars.xml

@@ -7,7 +7,7 @@
   -->
 
 <sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
-    android:accountType="bitfire.at.davdroid"
+    android:accountType="@string/account_type"
     android:contentAuthority="com.android.calendar"
     android:supportsUploading="true"
     android:isAlwaysSyncable="true" />

app/src/main/res/xml/sync_tasks.xml

@@ -7,6 +7,6 @@
   -->
 
 <sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
-    android:accountType="bitfire.at.davdroid"
+    android:accountType="@string/account_type"
     android:contentAuthority="org.dmfs.tasks"
     android:supportsUploading="true" />