src/version.c: Move internal documentation before includes.

The internal documentation generator only works if the file
description comment appears before the first #include line.

Fixes commit f277087d2a.

docs/C_SOURCE_FILES

@@ -264,6 +264,7 @@ src/tmpdirs.c
 src/umask.c
 src/unit-tests.c
 src/utils.c
+src/version.c
 src/wait.c
 src/whole-file.c
 test-tool/test-tool.c

src/version.c

@@ -16,6 +16,10 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/**
+ * This file provides simple version number management.
+ */
+
 #include <config.h>
 
 #include <string.h>
@@ -26,10 +30,6 @@
 #include "guestfs.h"
 #include "guestfs-internal.h"
 
-/**
- * This file provides simple version number management.
- */
-
 COMPILE_REGEXP (re_major_minor, "(\\d+)\\.(\\d+)", 0)
 
 static int version_from_x_y_or_x (guestfs_h *g, struct version *v, const char *str, const pcre *re, bool allow_only_x);