lib: Add tst_dev_fs_type() function

The function returns filesystem type to be used for testing.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
diff --git a/lib/ltp_priv.h b/lib/ltp_priv.h
index 8fec67f..9507e9d 100644
--- a/lib/ltp_priv.h
+++ b/lib/ltp_priv.h
@@ -32,6 +32,11 @@
  */
 #define TEMPDIR	"/tmp"
 
+/*
+ * Default filesystem to be used for tests.
+ */
+#define DEFAULT_FS_TYPE "ext2"
+
 /* environment variables for controlling  tst_res verbosity */
 #define TOUT_VERBOSE_S  "VERBOSE"	/* All test cases reported */
 #define TOUT_NOPASS_S   "NOPASS"	/* No pass test cases are reported */