openvswitch: fix build for gcc versions below 4.9

Seems that while fixing the build for GCC 4.9
I broke the build for GCC 4.8, because that KCFLAG I added
causes a build error (since it's not recognized).

The fix is to add KCFLAG only when GCC 4.9 is used.

OpenVSwitch now builds successfully with GCC 4.8 and 4.9.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
openvswitch: add patch "datapath: Backport __ip_select_ident() function"

Signed-off-by: Alexandru Ardelean <aa@ocedo.com>
Merge pull request #485 from commodo/ovs-build-fix

openvswitch: fix build for gcc versions below 4.9
Merge pull request #486 from commodo/ovs-build-fix2

openvswitch: add patch "datapath: Backport __ip_select_ident() function"
luci-app-lxc: code cleanup

Number of suggested rewrites:
* use lua ubus bindings instead of os.execute
* combine multiple actions to use same handler 'lxc_action' and pass
actions as arguments to consolidate code
* read openwrt version from lua directly
* start using String.prototype.format for string formatting

Also, drop 'rename' and 'clone' until they are fully functional on all
platforms.

Thanks Jo-Philipp for suggestions on how to improve the code.

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>