client: drop inode when rmdir request finishes

client: drop inode when rmdir request finishes

Current client code relies on cap message to trim unlinked inode
from cache. This method is too sensitive to message ordering. If
client receives the cap message while directory inode still contains
dentries that are referenced by unsafe requests, the inode can't
get trimmed.

The fix is, when rmdir/rename request finishes, try trimming the
unlinked inode again.

Fixes: #11339
Signed-off-by: Yan, Zheng <zyan@redhat.com>