fix FromPath not return go package

I found bug when I call :GoCurTest , It return error message

```
can't load package: package /Users/Thanabodee/src/Go/poker/src/github.com/wingyplus/gofizzbuzz: import "/Users/Thanabodee/src/Go/poker/src/github.com/wingyplu
s/gofizzbuzz": cannot import absolute path
```

I debug and found FromPath return absolute path not a go package path. 

This is result from :CurPkg

```
/Users/Thanabodee/src/Go/poker/src/github.com/wingyplus/gofizzbuzz
```