Treat errors when retrieving security policy as policy violation.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Use ipsec4_in_reject() to simplify ip_ipsec_fwd() and ip_ipsec_input().
ipsec4_in_reject() does the same things, also it counts policy violation
errors.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Add myself.