ipsec: fix length check when adding footer+icv
ipsec: fix length check when adding footer+icv

Length check must also take current_data into account.

Type: fix

Change-Id: I7a1b1752868892d40f59490d05452ef24565cca6
Signed-off-by: Benoît Ganne <38aad8ffcfa407b890d258e568f161530f66882d@cisco.com>

FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp