ic: Fix vxlan encap mode. #3388

Job	Run time
Prepare container	1m 5s
linux rpm fedora	6m 59s
osx clang --disable-ssl	1m 56s
linux gcc --disable-ssl	2m 33s
linux clang --disable-ssl	2m 43s
linux gcc test -300	10m 10s
linux gcc test 301-600	7m 29s
linux gcc test 601- unstable	7m 32s
linux clang test sanitizers -300	13m 30s
linux clang test sanitizers 301-600	10m 5s
linux clang test sanitizers 601- unstable	12m 48s
linux gcc test -ljemalloc -300	10m 42s
linux gcc test -ljemalloc 301-600	7m 30s
linux gcc test -ljemalloc 601- unstable	7m 42s
linux gcc system-test-dpdk dpdk -100	16m 52s
linux gcc system-test-dpdk dpdk 101- unstable	16m 31s
linux gcc system-test-userspace -100	16m 4s
linux gcc system-test-userspace 101- unstable	15m 22s
linux gcc system-test -100	18m 10s
linux gcc system-test 101- unstable	19m 49s
linux clang system-test sanitizers -100	20m 6s
linux clang system-test sanitizers 101- unstable	22m 11s
linux x86 gcc --disable-ssl	2m 41s
	4h 10m 30s

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