Correct output

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

bin/check_go_path

@@ -15,5 +15,5 @@ while [ ${#} -gt 1 ]; do
 done
 
 echo "go-ipfs must be built from within your \$GOPATH directory."
-echo "expected within '$GOPATH' but got '$PWD'"
+echo "expected within '$(go env GOPATH)' but got '$PWD'"
 exit 1