Bug 1108564 - Move share_overlay_background.9.png to hdpi directory to avoid crashes on resource-constrained builds. r=rnewman

--HG--
rename : mobile/android/base/resources/drawable-xhdpi/share_overlay_background.9.png => mobile/android/base/resources/drawable-hdpi/share_overlay_background.9.png
extra : rebase_source : 55095639ff6df78723fe71dc564f2222807f3bd7
extra : amend_source : 0dcfdc3af41464438de382c57e5c195dae2fb21d