Function SilcClientPendingDestructor
SYNOPSIS
typedef void (*SilcClientPendingDestructor)(void *context);
DESCRIPTION
Pending Command callback destructor. This is called after calling the
pending callback or if error occurs while processing the pending command.
If error occurs then the callback won't be called at all, and only this
destructor is called. The `context' is the context given for the function
silc_client_command_pending.