util: move ENODATA redefine to internal.h

FreeBSD lacks ENODATA, and viruuid.c redefines it to EIO, but it's not
actually using it. On the other hand, we have virrandom.c that's using
ENODATA. So make this re-definition common by moving it to internal.h,
so all the current and possible future users don't need to care about
that.

src/internal.h

@@ -517,4 +517,8 @@ enum {
     EXIT_ENOENT = 127, /* Could not find program to exec */
 };
 
+# ifndef ENODATA
+#  define ENODATA EIO
+# endif
+
 #endif                          /* __VIR_INTERNAL_H__ */

src/util/viruuid.c

@@ -46,10 +46,6 @@
 
 VIR_LOG_INIT("util.uuid");
 
-#ifndef ENODATA
-# define ENODATA EIO
-#endif
-
 static unsigned char host_uuid[VIR_UUID_BUFLEN];
 
 static int