Remove unnecessary struct2interface dependency (#13929)

* Remove unnecessary struct2interface dependency

Running go mod tidy on the repo removes it.
This was also preventing 1.14beta from running the repo,
because now it verifies modules.txt with go.mod, which had a mismatch.

* fixing CI

* Fix test-server target

* Fix some discrepancies in vendor

* Removing the Makefile target for now

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

go.mod

@@ -41,7 +41,7 @@ require (
 	github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428
 	github.com/jaytaylor/html2text v0.0.0-20190408195923-01ec452cbe43
 	github.com/jmoiron/sqlx v1.2.0
-	github.com/jonboulle/clockwork v0.1.0
+	github.com/jonboulle/clockwork v0.1.0 // indirect
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/lib/pq v1.3.0
 	github.com/magiconair/properties v1.8.1 // indirect
@@ -66,8 +66,6 @@ require (
 	github.com/pelletier/go-toml v1.6.0 // indirect
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.4.0
-	github.com/prometheus/client_model v0.2.0
-	github.com/reflog/struct2interface v0.3.0 // indirect
 	github.com/rs/cors v1.7.0
 	github.com/russellhaering/goxmldsig v0.0.0-20180430223755-7acd5e4a6ef7
 	github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd