Jenkinsfile: Fix some more variable syntax.

Jenkinsfile

@@ -9,7 +9,7 @@ node {
          stage 'test'
          sh 'env'
          sh 'curl https://glide.sh/get | sh'
-         sh 'mv $GOPATH/src/github.com/UNINETT ${GOPATH}/src/github.com/uninett'
+         sh 'mv $GOPATH/src/github.com/UNINETT $GOPATH/src/github.com/uninett'
          sh 'cd $GOPATH/src/github.com/uninett/jwt-tokenissuer'
          sh 'glide install'
          sh 'make test'
@@ -22,7 +22,7 @@ node {
          stage 'package'
          unstash 'binary'
          sh 'mv jwt-tokenissuer /src/'
-         sh 'fpm -s dir /src=/opt/jwt-tokenissuer -t deb -n jwt-tokenissuer -v ${VERSION_STRING}'
+         sh 'fpm -s dir /src=/opt/jwt-tokenissuer -t deb -n jwt-tokenissuer -v $VERSION_STRING'
          archive includes: '*.deb'
      }
 }