go.mod: remove unneeded indirect for "mgo" and "gocheck"

We don't appear to actually need to constrain these, and removing these decls may help avoid the need for `bzr` to install all the dependencies.

go.mod

@@ -117,6 +117,4 @@ require (
 	google.golang.org/api v0.1.0
 	google.golang.org/grpc v1.18.0
 	gopkg.in/vmihailenco/msgpack.v2 v2.9.1 // indirect
-	labix.org/v2/mgo v0.0.0-20140701140051-000000000287 // indirect
-	launchpad.net/gocheck v0.0.0-20140225173054-000000000087 // indirect
 )

go.sum

@@ -210,8 +210,6 @@ github.com/hashicorp/memberlist v0.1.0 h1:qSsCiC0WYD39lbSitKNt40e30uorm2Ss/d4JGU
 github.com/hashicorp/memberlist v0.1.0/go.mod h1:ncdBp14cuox2iFOq3kDiquKU6fqsTBc3W6JvZwjxxsE=
 github.com/hashicorp/serf v0.0.0-20160124182025-e4ec8cc423bb h1:ZbgmOQt8DOg796figP87/EFCVx2v2h9yRvwHF/zceX4=
 github.com/hashicorp/serf v0.0.0-20160124182025-e4ec8cc423bb/go.mod h1:h/Ru6tmZazX7WO/GDmwdpS975F019L4t5ng5IgwbNrE=
-github.com/hashicorp/terraform-config-inspect v0.0.0-20190208230122-b0707673339c h1:nCnsfi66NloVlmquh5dLox5yBwQk5CV5s2roWvbstnE=
-github.com/hashicorp/terraform-config-inspect v0.0.0-20190208230122-b0707673339c/go.mod h1:ItvqtvbC3K23FFET62ZwnkwtpbKZm8t8eMcWjmVVjD8=
 github.com/hashicorp/terraform-config-inspect v0.0.0-20190327195015-8022a2663a70 h1:oZm5nE11yhzsTRz/YrUyDMSvixePqjoZihwn8ipuOYI=
 github.com/hashicorp/terraform-config-inspect v0.0.0-20190327195015-8022a2663a70/go.mod h1:ItvqtvbC3K23FFET62ZwnkwtpbKZm8t8eMcWjmVVjD8=
 github.com/hashicorp/vault v0.10.4 h1:4x0lHxui/ZRp/B3E0Auv1QNBJpzETqHR2kQD3mHSBJU=
@@ -512,9 +510,5 @@ grpc.go4.org v0.0.0-20170609214715-11d0a25b4919/go.mod h1:77eQGdRu53HpSqPFJFmuJd
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 howett.net/plist v0.0.0-20181124034731-591f970eefbb/go.mod h1:vMygbs4qMhSZSc4lCUl2OEE+rDiIIJAIdR4m7MiMcm0=
-labix.org/v2/mgo v0.0.0-20140701140051-000000000287 h1:L0cnkNl4TfAXzvdrqsYEmxOHOCv2p5I3taaReO8BWFs=
-labix.org/v2/mgo v0.0.0-20140701140051-000000000287/go.mod h1:Lg7AYkt1uXJoR9oeSZ3W/8IXLdvOfIITgZnommstyz4=
-launchpad.net/gocheck v0.0.0-20140225173054-000000000087 h1:Izowp2XBH6Ya6rv+hqbceQyw/gSGoXfH/UPoTGduL54=
-launchpad.net/gocheck v0.0.0-20140225173054-000000000087/go.mod h1:hj7XX3B/0A+80Vse0e+BUHsHMTEhd0O4cpUHr/e/BUM=
 sourcegraph.com/sourcegraph/go-diff v0.5.0/go.mod h1:kuch7UrkMzY0X+p9CRK03kfuPQ2zzQcaEFbx8wA8rck=
 sourcegraph.com/sqs/pbtypes v0.0.0-20180604144634-d3ebe8f20ae4/go.mod h1:ketZ/q3QxT9HOBeFhu6RdvsftgpsbFHBF5Cas6cDKZ0=