Enhanced support for Travis CI: build with and without DPDK support, use varioius compilers (GCC 5/6/7)
Enhanced support for Travis CI: build with and without DPDK support, use varioius compilers (GCC 5/6/7)

Signed-off-by: Vladimir Krivopalov <8393b6f566d8ebdefd4d2517fe16f44423413d9c@gmail.com>
Message-Id: <20171004032435.805-1-8393b6f566d8ebdefd4d2517fe16f44423413d9c@gmail.com>

syuu1228/seastar,cloudius-systems/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,scylladb/seastar,avikivity/seastar,dreamsxin/seastar,syuu1228/seastar,dreamsxin/seastar,cloudius-systems/seastar,avikivity/seastar,cloudius-systems/seastar,dreamsxin/seastar,scylladb/seastar