Add version number to --help output

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/init.c b/init.c
index 98e10f7..9b386c5 100644
--- a/init.c
+++ b/init.c
@@ -1021,6 +1021,7 @@
 
 static void usage(const char *name)
 {
+	printf("%s\n", fio_version_string);
 	printf("%s [options] [job options] <job file(s)>\n", name);
 	printf("\t--debug=options\tEnable debug logging\n");
 	printf("\t--output\tWrite output to file\n");