audit: remove audit_finish_fork as it can't be called

Audit entry,always rules are not allowed and are automatically changed in
exit,always rules in userspace.  The kernel refuses to load such rules.

Thus a task in the middle of a syscall (and thus in audit_finish_fork())
can only be in one of two states: AUDIT_BUILD_CONTEXT or AUDIT_DISABLED.
Since the current task cannot be in AUDIT_RECORD_CONTEXT we aren't every
going to actually use the code in audit_finish_fork() since it will
return without doing anything.  Thus drop the code.

Signed-off-by: Eric Paris <eparis@redhat.com>

kernel/fork.c

@@ -1525,8 +1525,6 @@ long do_fork(unsigned long clone_flags,
 			init_completion(&vfork);
 		}
 
-		audit_finish_fork(p);
-
 		/*
 		 * We set PF_STARTING at creation in case tracing wants to
 		 * use this to distinguish a fully live task from one that