Gxed Badger hack: use the same net/trace everywhere

[hsanjuan]

net/trace cannot be imported on different versions from different modules.

Additionally, we also cannot export ExpVars with the same names from two different
packages (one being gxed-badger and the other being the go-modded one). Since those
two packages have different import paths, go considers them different and runs
init() twice, causing the issues.

[hsanjuan]

@Stebalien I have isolated this change here so that the migrations PR is cleaner.

[Stebalien]

If we use go mod vendor, we need to make sure to build with go build -mod=vendor. Although I guess this + go.sum meets the "works if everything else goes down" and "doesn't" change requirements.

[Stebalien]

That's why I avoided using go mod vendor for all of our other dependencies (e.g., gx, etc.). go build will still fail if the source goes down unless you specify go build -mod=vendor.

[Stebalien]

LGTM

[hsanjuan]

@Stebalien you commented while I was vendoring all the things properly. See now?

[hsanjuan]

So now travis will catch if things not vendored