Remove android: attributes from library manifest

If an app using this library sets different values for allowBackup /
supportsRtl, the build will fail because of:

Attribute application@allowBackup value=(false) from AndroidManifest.xml:11:9-36
is also present at [com.github.sevar83:indeterminate-checkbox:1.0.5] AndroidManifest.xml:12:9-35 value=(true).

Just remove the attributes as they are not needed.

library/src/main/AndroidManifest.xml

@@ -1,11 +1 @@
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="com.buildware.widget.indeterm">
-
-    <application android:allowBackup="true"
-                 android:label="@string/app_name"
-                 android:supportsRtl="true"
-        >
-
-    </application>
-
-</manifest>
+<manifest package="com.buildware.widget.indeterm" />