[Android][SysApps] Change the unit of storage capacity to byte.

According to the spec
http://device-capabilities.sysapps.org/#systemstorage-interface ,
the ``capacity`` should be in bytes but the original implementation
is in kilobytes.
Merge pull request #1322 from itlodge/fix_storage_unit

[Android][SysApps] Change the unit of storage capacity to byte.