Correct $ANDROID_HOME string empty check (#37064)
Summary:
Updated file to correct shell code to test whether $ANDROID_HOME env variable is empty or not.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37064
Differential Revision: D21181787
Pulled By: IvanKobzarev
fbshipit-source-id: 40c1d79d0fb730c7f68aa7472ce9b2398e91f2a2
