[single] Thread safety bug fix

[single] Thread safety bug fix

Added bug fix for thread safe usage
Single shot API use single handle lock for making all its API call thread safe
However, the call to close the API destroys the handle itself making the
call to close not thread safe
Added a global lock to make closing of handles thread safe

Further, all the single handle locks are acquired inside the global lock
to ensure that single handle is not closed while the magic has been verified
and the local lock is not acquired

Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>