VTLAM: VTEST -> VCI

[Poul-Henning Kamp]

During discussions with Nils yesterday it became clear that the
overloading of "VTEST" for both the non-native version of varnishtest
and for our CI setup is silly.

To that end, I plan to rename the VTEST stuff to VCI as soon as a
round tuit can be spared.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.