Trebuchet : Fix asset xml parsing

openXmlResourceParser only seems to work for compiled resources.
This addresses the issue introduced in http://review.cyanogenmod.org/#/c/49629/6
where icon packs which relied on appfilter.xml to provide icons broke.

Change-Id: Ia1c92258638faa8ebc7523762e37ae532aba7d72
Merge remote-tracking branch 'upstream/cm-10.2' into HEAD