ipv4: fix memory leaks in udp_sendmsg, ping_v4_sendmsg

ipv4: fix memory leaks in udp_sendmsg, ping_v4_sendmsg

Fix more memory leaks in ip_cmsg_send() callers. Part of them were fixed
earlier in 49587447b55d.

* udp_sendmsg one was there since the beginning when linux sources were
  first added to git;
* ping_v4_sendmsg one was copy/pasted in cfce3383c7be.

Whenever return happens in udp_sendmsg() or ping_v4_sendmsg() IP options
have to be freed if they were allocated previously.

Add label so that future callers (if any) can use it instead of kfree()
before return that is easy to forget.

Fixes: cfce3383c7be (net: ipv4: add IPPROTO_ICMP socket kind)
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>