EX-3409 pcc: add owner capacity check for open attach

EX-3409 pcc: add owner capacity check for open attach

This patch adds owner and capacity check when try to auto attach
at the open() time.
Add sanity-pcc test_43.

For the command "lfs pcc attach_fid", make it more convenient by
the way that the parameter "-m" is not mandatory required when
specifying the mount point.

Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: Icb8cbddb64c5712e2db970120b06fc1a0216c332
Reviewed-on: https://review.whamcloud.com/44123
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Feng, Lei <flei@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>