Add condition to skip invoking focus callback in case of unregistering without releas...

Add condition to skip invoking focus callback in case of unregistering without releasing focus

For session backward compatibility, there can be serveral nodes that have focus in the same process.
Check focus status of other node that has same pid as the focus node's that requested to unregister
to skip invoking focus callback if a node with acquired status exists.

[Version] 0.10.102
[Profile] Common
[Issue Type] Bug fix

Change-Id: I2c213ecacc9da743cc2b0359bf57ba5b38c17c82
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>