avutil/avstring: Remove obsolete version.h inclusion

Forgotten in 30e1e7e0.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/avstring.c

@@ -32,7 +32,6 @@
 #include "bprint.h"
 #include "error.h"
 #include "macros.h"
-#include "version.h"
 
 int av_strstart(const char *str, const char *pfx, const char **ptr)
 {

libavutil/avstring.h

@@ -24,7 +24,6 @@
 #include <stddef.h>
 #include <stdint.h>
 #include "attributes.h"
-#include "version.h"
 
 /**
  * @addtogroup lavu_string

libavutil/spherical.c

@@ -19,6 +19,7 @@
  */
 
 #include "avstring.h"
+#include "macros.h"
 #include "mem.h"
 #include "spherical.h"