system-dpdk: Fix race in some vhost-user client MTU test. #258

Job	Run time
linux rpm fedora	4m 37s
osx clang --disable-ssl	3m 9s
dpdk gcc	17s
linux deb no dpdk	4m 43s
linux gcc --disable-ssl	2m 13s
linux clang --disable-ssl	3m 49s
linux gcc c99	2m 11s
linux clang c99	2m 9s
linux gcc test	6m 40s
linux clang test asan	11m 6s
linux clang test ubsan	7m 33s
linux gcc test --enable-shared	9m 0s
linux clang test --enable-shared	8m 53s
linux gcc check check-dpdk dpdk	7m 14s
linux clang check check-dpdk dpdk	7m 44s
linux gcc test -ljemalloc	6m 36s
linux clang test -ljemalloc	8m 2s
linux gcc --enable-afxdp	2m 6s
linux clang --enable-afxdp	3m 24s
linux gcc dpdk --enable-shared	3m 21s
linux clang dpdk --enable-shared	2m 41s
linux gcc dpdk-shared	3m 9s
linux clang dpdk-shared	2m 41s
linux gcc dpdk-shared --enable-shared	2m 59s
linux clang dpdk-shared --enable-shared	3m 1s
linux gcc m32 --disable-ssl	2m 18s
	2h 1m 36s

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