Fill in cstat if exec_setup() fails. Previously it was only filled

in for an execve() failure.  Fixes an unkillable sudo process when
exec_setup() fails and I/O logging is enabled.

src/exec.c

@@ -184,11 +184,11 @@ exec_cmnd(struct command_details *details, struct command_status *cstat,
 	    sudo_execve(details->command, details->argv, details->envp,
 		ISSET(details->flags, CD_NOEXEC));
 	}
+    }
     cstat->type = CMD_ERRNO;
     cstat->val = errno;
     sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to exec %s: %s",
 	details->command, strerror(errno));
-    }
     debug_return;
 }