Update build script

- GOPATH is no longer required
- fzf repository does not have to be in GOPATH
- Build Linux binary with Go 1.5.3

src/Dockerfile.arch

@@ -10,7 +10,6 @@ RUN cd / && curl \
     https://storage.googleapis.com/golang/go1.4.2.linux-amd64.tar.gz | \
     tar -xz && mv go go1.4
 
-ENV GOPATH /go
 ENV GOROOT /go1.4
 ENV PATH /go1.4/bin:$PATH
 
@@ -20,9 +19,6 @@ RUN echo '[multilib]' >> /etc/pacman.conf && \
     pacman-db-upgrade && yes | pacman -Sy gcc-multilib lib32-ncurses && \
     cd $GOROOT/src && GOARCH=386 ./make.bash
 
-# Volume
-VOLUME /go
-
 # Default CMD
-CMD cd /go/src/github.com/junegunn/fzf/src && /bin/bash
+CMD cd /fzf/src && /bin/bash