libcutils: fs_config read from file

Intention is to read from ${OUT}/system/etc/fs_config_dirs and
${OUT}/system/etc/fs_config_files on host. And
/system/etc/fs_config_dirs and /system/etc/config_files
on target systems.

Bug: 19908228
Change-Id: Ieaedd99e88c7f7f717878d9344c387ddf335ccbb
1 file changed