sstate-cache-management.sh: update for the SSTATE_MIRRORS
Several fixes:
* We have put the sstate file to SSTATE_DIR/??/ currently, but the
sstate file on the SSTATE_MIRRORS or the obsolete one is still in
SSTATE_DIR/ (no subdir), update the script to support manage them.
* Remove the related ".done" file in the SSTATE_DIR.
* Add a "-L, --follow-symlink" which will remove both the symbol link and
the destination file
* Change the "ls -u file_list" (access time) to "ls -t file_list"
(change tiem), since the "ls -u" and readlink will change the
symlink's access time, which would make the result inconsistent.
A solution is save the access time before every "ls -u" and "readlink",
save it back after the command, but this would cause performance lost
since it needs check each file and modify the symlink's status. Use
the "-t" doesn't cause much different.
[YOCTO #2897]
Signed-off-by: Robert Yang <liezhi.yang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
