[MINOR] Update eagle-env.sh to support MINGW64
[MINOR] Update eagle-env.sh to support MINGW64

Author: Qingwen Zhao <qingwen220@gmail.com>

Closes #496 from qingwen220/updateServerScript.

baibaichen/eagle,haoch/incubator-eagle,baibaichen/eagle,baibaichen/eagle,anyway1021/incubator-eagle,DadanielZ/incubator-eagle,DadanielZ/incubator-eagle,yonzhang/incubator-eagle,zombieJ/incubator-eagle,haoch/incubator-eagle,1haodian/eagle,anyway1021/incubator-eagle,DadanielZ/incubator-eagle,zombieJ/incubator-eagle,anyway1021/incubator-eagle,qingwen220/eagle,haoch/incubator-eagle,haoch/Eagle,anyway1021/incubator-eagle,haoch/Eagle,yonzhang/incubator-eagle,zombieJ/incubator-eagle,qingwen220/eagle,qingwen220/eagle,baibaichen/eagle,haoch/Eagle,yonzhang/incubator-eagle,haoch/incubator-eagle,1haodian/eagle,DadanielZ/incubator-eagle,DadanielZ/incubator-eagle,zombieJ/incubator-eagle,yonzhang/incubator-eagle,1haodian/eagle,DadanielZ/incubator-eagle,haoch/incubator-eagle,qingwen220/eagle,anyway1021/incubator-eagle,baibaichen/eagle,zombieJ/incubator-eagle,haoch/incubator-eagle,1haodian/eagle,1haodian/eagle,yonzhang/incubator-eagle,qingwen220/eagle,haoch/Eagle,haoch/Eagle,anyway1021/incubator-eagle