Merge pull request #1243 from ezchi/get-default-go-environment-variables-with-go-binary

Use go binary to get default GOROOT and GOPATH

plugins/available/go.plugin.bash

@@ -5,7 +5,7 @@ about-plugin 'go environment variables & path configuration'
 
 [ ! command -v go &>/dev/null ] && return
 
-export GOROOT=${GOROOT:-$(go env | grep GOROOT | cut -d'"' -f2)}
+export GOROOT=${GOROOT:-$(go env GOROOT)}
 pathmunge "${GOROOT}/bin"
-export GOPATH=${GOPATH:-"$HOME/go"}
+export GOPATH=${GOPATH:-$(go env GOPATH)}
 pathmunge "${GOPATH}/bin"