stress_floppy: Add 'datafiles'

* Modify 'io_floppy'.

* Move '1K_file', 'dd_file' and 'generate.sh' into 'datafiles'.

* Install '1K_file', 'dd_file' and 'generate.sh' to
  'testcases/data/stress_floppy'.

* Some cleanup.

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
diff --git a/runtest/io_floppy b/runtest/io_floppy
index 3f50caa..c861d9f 100644
--- a/runtest/io_floppy
+++ b/runtest/io_floppy
@@ -1 +1 @@
-stress_floppy export TCdat=$LTPROOT/testcases/kernel/io/stress_floppy; stress_floppy
+stress_floppy stress_floppy