go.mod: workaround missing redirect

This fix is needed because we were hitting:
```
vbom.ml/[email protected]: unrecognized import path "vbom.ml/util": reading https://vbom.ml/util?go-get=1: 503 Service Unavailable
```

Source for the workaround:
golang/dep#1169

The fix consists in simply enforcing what the redirect was supposed to
do. It seems that starting version 4.6 openshift/library-go no longer
depends on this package, so this workaround can be removed when we will
depend on 4.6

Signed-off-by: Francesco Romani <[email protected]>

Author: ffromani

go.mod

@@ -71,3 +71,5 @@ replace (
 	github.com/operator-framework/operator-sdk => github.com/operator-framework/operator-sdk v0.18.1
 	golang.org/x/tools => golang.org/x/tools v0.0.0-20191206213732-070c9d21b343
 )
+
+replace vbom.ml/util => github.com/fvbommel/util v0.0.0-20180919145318-efcd4e0f9787

go.sum

@@ -400,6 +400,7 @@ github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/fsouza/fake-gcs-server v1.7.0/go.mod h1:5XIRs4YvwNbNoz+1JF8j6KLAyDh7RHGAyAK3EP2EsNk=
 github.com/fsouza/go-dockerclient v0.0.0-20171004212419-da3951ba2e9e/go.mod h1:KpcjM623fQYE9MZiTGzKhjfxXAV9wbyX2C1cyRHfhl0=
+github.com/fvbommel/util v0.0.0-20180919145318-efcd4e0f9787/go.mod h1:AlRx4sdoz6EdWGYPMeunQWYf46cKnq7J4iVvLgyb5cY=
 github.com/garyburd/redigo v0.0.0-20150301180006-535138d7bcd7/go.mod h1:NR3MbYisc3/PwhQ00EMzDiPmrwpPxAn5GI05/YaO1SY=
 github.com/getsentry/raven-go v0.0.0-20190513200303-c977f96e1095/go.mod h1:KungGk8q33+aIAZUIVWZDr2OfAEBsO49PX4NzFV5kcQ=
 github.com/getsentry/raven-go v0.2.0/go.mod h1:KungGk8q33+aIAZUIVWZDr2OfAEBsO49PX4NzFV5kcQ=
@@ -1920,5 +1921,3 @@ sigs.k8s.io/yaml v1.2.0 h1:kr/MCeFWJWTwyaHoR9c8EjH9OumOmoF9YGiZd7lFm/Q=
 sigs.k8s.io/yaml v1.2.0/go.mod h1:yfXDCHCao9+ENCvLSE62v9VSji2MKu5jeNfTrofGhJc=
 sourcegraph.com/sourcegraph/appdash v0.0.0-20190731080439-ebfcffb1b5c0/go.mod h1:hI742Nqp5OhwiqlzhgfbWU4mW4yO10fP+LoT9WOswdU=
 sourcegraph.com/sqs/pbtypes v0.0.0-20180604144634-d3ebe8f20ae4/go.mod h1:ketZ/q3QxT9HOBeFhu6RdvsftgpsbFHBF5Cas6cDKZ0=
-vbom.ml/util v0.0.0-20160121211510-db5cfe13f5cc/go.mod h1:so/NYdZXCz+E3ZpW0uAoCj6uzU2+8OWDFv/HxUSs7kI=
-vbom.ml/util v0.0.0-20180919145318-efcd4e0f9787/go.mod h1:so/NYdZXCz+E3ZpW0uAoCj6uzU2+8OWDFv/HxUSs7kI=