envsetup: Always look up JAVA_HOME path

Change-Id: I8b0641eb107cd095079bb17f92e99730f532fda7
diff --git a/envsetup.sh b/envsetup.sh
index 7b5c069..aa14aef 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -2055,7 +2055,7 @@
               export JAVA_HOME=$(/usr/libexec/java_home -v 1.7)
               ;;
           *)
-              export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
+              export JAVA_HOME=$(dirname $(dirname $(dirname $(readlink -f $(which java)))))
               ;;
       esac