Fix the unexpected slave object deleteing.

Fix the unexpected slave object deleteing.

1. slave_deactivate function should not release the slave object directly even though it has ZERO instances.

2. slave_deactivate function is changed to static one.
   It only used in slave_life.c file.
   so I specify its scope to slave_life.c file.

3. Do not deactivate the slave again if it is already deactivated.
   So before call the deactivate function, check its states whether it is activated or not

[model] Redwood,Kiran,B3(Wearable)
[binary_type] AP
[customer] Docomo/Orange/ATT/Open
[issue#] N/A
[problem]
[cause]
[solution]
[team] HomeTF
[request]
[horizontal_expansion]

Change-Id: I6fa8025201a7e9e141a8a3a9e81148122c65682c