strace.c: pass signal number to cleanup()

strace.c: pass signal number to cleanup()

* strace.c (die): Pass 0 as an argument to cleanup().
(cleanup): Add fatal_sig parameter, remove the local variable
of the same name, do not use interrupted.
(terminate): Initialise a new local variable "sig" with "interrupted",
pass it to cleanup() and use it instead of "interrupted" for exit_code
initialisation.