idegen: don't use hardcoded out directory

Use the host bin dir defined by the build env.

Change-Id: Icee817d647d44e77a29688dc2238c6490cc6f807
diff --git a/tools/idegen/idegen.sh b/tools/idegen/idegen.sh
index d7e6986..1c3ba18 100755
--- a/tools/idegen/idegen.sh
+++ b/tools/idegen/idegen.sh
@@ -5,7 +5,7 @@
     exit 1
 fi
 
-idegenjar=`find out -name idegen.jar -follow | grep -v intermediates`
+idegenjar=`find $ANDROID_HOST_OUT -name idegen.jar -follow | grep -v intermediates`
 if [ "" = "$idegenjar" ]; then
     echo "Couldn't find idegen.jar. Please run make first."
 else