travis: remove gocc go.mod work around
MODIFY
.travis/install-gocc.sh
.travis/install-gocc.sh
@@ -4,7 +4,6 @@ set -ex
# TODO(kortschak): Replace this with versioned go get when
# all our supported versions of Go support it.
-export GO111MODULE=auto
mkdir -p $GOPATH/src/github.com/goccmack
git clone https://github.com/goccmack/gocc.git $GOPATH/src/github.com/goccmack/gocc
cd $GOPATH/src/github.com/goccmack/gocc

travis: remove gocc go.mod work around