Actually skip excluded files from tar backup

Change-Id: Ibbc4eb2eb89863ccb2a15f5a3b5092fb10fcbcc0
Cleanup DU Get_Folder_Size function

Change-Id: I3c686c7c3a171f130d299fae586dc811cad0d3a9
Fix /data backup size if contains media subdirs

/data/*/media directories are mistakenly being excluded from the size
calculation. Change to absolute dir exclude so that only /data/media is
excluded.

Change-Id: I6e97604d44e6ea2bdf7dfd8c68a2f90ba6d44415