Apply defer macros to callbacks in cynara async client

Apply defer macros to callbacks in cynara async client

After all cynara library functions were sorrounded with try catch
macros causing all exceptions to be caught, there is no way of
throwning an exception from inside of callback function.

This is where defer macros mechanism can be applied.
Now all exceptions will be rethrown after comming back from
libcynara-client-async API functions.

Change-Id: I9743557631f2b13cecddf33cb072f280ae689d0a