Fix build.sh

Change-Id: I50832bb529f636348554c1cd933f89aed961fe98
diff --git a/build.sh b/build.sh
index f730e53..038f8ac 100755
--- a/build.sh
+++ b/build.sh
@@ -203,6 +203,7 @@
 	mkdir -p $TEMP_MBTK_DIR/mbtk/include
 	mkdir -p $TEMP_MBTK_DIR/mbtk/rootfs/bin
 	mkdir -p $TEMP_MBTK_DIR/mbtk/rootfs/lib
+	mkdir -p $TEMP_MBTK_DIR/mbtk/rootfs/etc
 	mkdir -p $TEMP_MBTK_DIR/mbtk/test
 	
 	copy_bin_and_lib $TEMP_MBTK_DIR/mbtk/rootfs