[build] fix jenkins build issue

Signed-off-by: Leo Chen <leo@harmony.one>

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/gorilla/mux v1.7.0
 	github.com/harmony-one/bls v0.0.0-20190309234102-1bd75ac96c09
 	github.com/hashicorp/golang-lru v0.5.1
+	github.com/ipfs/go-datastore v3.2.0+incompatible
 	github.com/libp2p/go-libp2p v0.0.2
 	github.com/libp2p/go-libp2p-crypto v0.0.1
 	github.com/libp2p/go-libp2p-discovery v0.0.1
@@ -30,4 +31,5 @@ require (
 	github.com/shirou/gopsutil v2.18.12+incompatible
 	golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2
 	google.golang.org/grpc v1.19.0
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 )