openvswitch: upgrade to version 2.7.0

openvswitch: upgrade to version 2.7.0

Notes:
- drop un-needed patches
- bump kernel support up to 4.9
- switch from git repo to release tarball
- use OVS intree kernel module ; seems that using the kernel module
  from the package has certain issues due to the glue/backport code
  that tries to adapt to many kernel versions and has a potential
  to mess up ; not to mention, the glue code makes the kmod
  a few times larger than it should be
- tested on x86_64 VM

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>