android: Re-autogen when AndroidManifest.xml.in changes.

Change-Id: I53cf6bf10f25702d9ae42afb6846411a3e31c187
android: Disable LibreOfficeUIActivity for now.

We should provide just one activity in the .apk; the browser should probably
show up when LibreOffice Viewer is started with no file to open...

Change-Id: I624afa00f7e8ddc649a272c1b08899e8aac887c9