Restore mDragInfo when deferring onDropComplete() for uninstall.

We moved mDragInfo = null to onDragEnd() since onDropComplete()
isn't called for pre-drags, but this led to NPE when returning
from unistall or app info since onDropComplete() is called after
onDragEnd() in this case. So now we restore a copy of mDragInfo.

Bug: 32415014
Change-Id: I7ef4fb7145c3c78039af1131e77538969db58141
1 file changed