Start using DPDK v1.7.1
We no longer need to init specific drivers or probe.

References:

- dpdk:a155d430119d
- dpdk:e5ffdd1457c0
Match DPDK's changed library names, and add rte_kvargs.
Update to match new DPDK target name: default -> native
Try disabling building KNI, so that we can work with travis' not-quite-ubuntu environment.
Merge pull request #9 from alex4nder/dpdk-1.7.1

Update to use DPDK v1.7.1