netperf package issue

[chunfuwen]

Issue description:
netperf is somehow used for case execution by tp-libvirt [1] and tp-qemu(I think).
And In avocado-vt, we maintain netperf source under virttest/shared/deps/netperf/netperf-2.6.x.tar.bz2.
But it is subject to changes since it need keep compatible with guest OS version change.
One practical example recently happened in PR[2].
Moreover, it is better that avocado-vt itself doesn't own "package management" since binary data is easily to become corrupt in github.

Therefore, I open this issue to seek more suggestions from all of you how to handle it more gracefully

[1]https://github.com/autotest/tp-libvirt/pull/3631
[2]https://github.com/avocado-framework/avocado-vt/pull/3131

[chunfuwen]

@luckyh
Just loop you in in case it has some impact on tp-qemu

@kylazhang
@smitterl
@dzhengfy
@chloerh
@Yingshun
@cliping

[luckyh]

Just FYI, in the age of Autotest, the patching works were usually accomplished by the below way:

1. creates standalone patch files and places them beside tarball
2. applies them before using

For example:
https://github.com/autotest/autotest-client-tests/tree/f35094f28e391b5feea7fc398f618cbb56dc23c5/scsi_testsuite
https://github.com/autotest/autotest-client-tests/blob/f35094f28e391b5feea7fc398f618cbb56dc23c5/scsi_testsuite/scsi_testsuite.py#L86-L88
https://github.com/avocado-framework/avocado-vt/blob/master/virttest/shared/control/scsi_testsuite_with_patch.control

[chunfuwen]

@luckyh ,thanks for your feedback