virttest.utils_net: Move method ip_link_ctl from macvtap class

[Xiangmin]

Change ip_link_ctl as global method in utils_net.

Signed-off-by: Xiangmin Han xhan@redhat.com

[Xiangmin]

@FengYang
I have checked tp-libvirt, tp-qemu and virt-test, the ip_link_ctl function is only called by the class macvtap methods. At the same, I have changed the callers which would use ip_link_ctl to use the
global one.

[zhouqt]

Hey @Xiangmin,

I'd ask why you need to put these functions global? IMO, you break the cohesion [1] of a class, I even prefer copying these function into your own script, to separating them from a class.

So please, is it the only way to make them global?

Thanks,
Tom

[1] http://en.wikipedia.org/wiki/Cohesion_(computer_science)

[ypu]

@zhouqt Agree with you about the break cohesion part. Just look through the code and find that ip_link is quite basic function for interface ops. So I guess we can put it from Macvtap class to the basic class Interface and use it through that class.

[Xiangmin]

Thanks @ypu and @zhouqt
I would change and send again.

[lmr]

@Xiangmin, please make the changes and rebase. this will allow your PR to be tested by Travis.

[Xiangmin]

Would add delete function in the original Interface class. So close this PR.