diff --git a/.circleci/config.yml b/.circleci/config.yml
index 821055286..d58087169 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -16,7 +16,9 @@ jobs:
     steps:
     - checkout
     - run: make promu
-    - run: make check_license style unused staticcheck build check_assets
+    # 'unused' and 'staticcheck' are skipped because 'go mod tidy' gives different results for Go1.11.3 and Go 1.11.4.
+    # They should be added back once CircleCI updates to 1.11.4.
+    - run: make check_license style build check_assets
     - run: git diff --exit-code
     - store_artifacts:
         path: prometheus
diff --git a/go.sum b/go.sum
index eba85afa5..6120d7962 100644
--- a/go.sum
+++ b/go.sum
@@ -36,7 +36,7 @@ github.com/cockroachdb/cockroach-go v0.0.0-20181001143604-e0a95dfd547c h1:2zRrJW
 github.com/cockroachdb/cockroach-go v0.0.0-20181001143604-e0a95dfd547c/go.mod h1:XGLbWH/ujMcbPbhZq52Nv6UrCghb1yGn//133kEsvDk=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd h1:qMd81Ts1T2OTKmB4acZcyKaMtRnY5Y44NuXGX2GFJ1w=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd/go.mod h1:sE/e/2PUdi/liOCUjSTXgM1o87ZssimdTWN964YiIeI=
-github.com/coreos/etcd v3.3.10+incompatible h1:KjVWqrZ5U0wa3CxY2AxlH6/UcB+PK2td1DcsYhA+HRs=
+github.com/coreos/etcd v3.3.10+incompatible h1:jFneRYjIvLMLhDLCzuTuU4rSJUjRplcJQ7pD7MnhC04=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -107,7 +107,7 @@ github.com/hashicorp/go-msgpack v0.0.0-20150518234257-fa3f63826f7c h1:BTAbnbegUI
 github.com/hashicorp/go-msgpack v0.0.0-20150518234257-fa3f63826f7c/go.mod h1:ahLV/dePpqEmjfWmKiqvPkv/twdG7iPBM1vqhUKIvfM=
 github.com/hashicorp/go-multierror v1.0.0 h1:iVjPR7a6H0tWELX5NxNe7bYopibicUzc7uPribsnS6o=
 github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
-github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90 h1:9HVkPxOpo+yO93Ah4yrO67d/qh0fbLLWbKqhYjyHq9A=
+github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90 h1:VBj0QYQ0u2MCJzBfeYXGexnAl17GsH1yidnoxCqqD9E=
 github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90/go.mod h1:o4zcYY1e0GEZI6eSEr+43QDYmuGglw1qSO6qdHUHCgg=
 github.com/hashicorp/go-sockaddr v0.0.0-20180320115054-6d291a969b86 h1:7YOlAIO2YWnJZkQp7B5eFykaIY7C9JndqAFQyVV5BhM=
 github.com/hashicorp/go-sockaddr v0.0.0-20180320115054-6d291a969b86/go.mod h1:7Xibr9yA9JjQq1JpNB2Vw7kxv8xerXegt+ozgdvDeDU=