Split version into separate include fio

Include it from the Windows version file, at least we only have
to update the version in two places now instead of three.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/init.c b/init.c
index 5c4441d..e3ff39c 100644
--- a/init.c
+++ b/init.c
@@ -23,6 +23,8 @@
 
 #include "lib/getopt.h"
 
+#include "fio_version.h"
+
 #if FIO_PATCH > 0
 static char fio_version_string[] =	__fio_stringify(FIO_MAJOR) "."	\
 					__fio_stringify(FIO_MINOR) "."	\