kernel: remove FillInVersion

No distributed package (nor any other I know of) still uses this, with
one exception: ParGAP, which however is unmaintained and already suffers
from other compilation issues. However, I actually did remove use of
FillInVersion from https://github.com/gap-packages/pargap, but no release
has been made from there since many other things remain broken.

src/debug.c

@@ -120,7 +120,6 @@ VoidFunc debug_func_pointers[] = {
     (VoidFunc)ENVI_FUNC,
     (VoidFunc)FEXS_FUNC,
     (VoidFunc)FibHash,
-    (VoidFunc)FillInVersion,
     (VoidFunc)FUNC,
 #ifdef HPCGAP
     (VoidFunc)GetTLS,

src/gap.h

@@ -234,14 +234,6 @@ enum {
 */
 
 
-/****************************************************************************
-**
-*F  FillInVersion -- obsolete function, only kept for backwards compatibility
-**  with packages using it.
-*/
-static inline void FillInVersion ( StructInitInfo * module ) {}
-
-
 /****************************************************************************
 **
 *F  InitBagNamesFromTable( <table> )  . . . . . . . . .  initialise bag names