Error in DirectFactorsFinder

[fingolfin]

During tests in https://github.com/gap-packages/ClassicalMaximals I've run into an error in RECOG.DirectFactorsFinder. It is a pretty obvious bug which I think this patch should fix; I made the context of the patch big enough to allow seeing the problem in the code (fgens[3] was not defined before; it only works most of the time because it aborts before ever getting to the code accessing it).

diff --git a/gap/projective/d247.gi b/gap/projective/d247.gi
index 7f82f56..00080ea 100644
--- a/gap/projective/d247.gi
+++ b/gap/projective/d247.gi
@@ -93,12 +93,13 @@ end;
 RECOG.DirectFactorsFinder := function(gens,facgens,k,eq)
   local equal,fgens,i,j,l,o,pgens,pr,z;
   fgens := [];
   pr := ProductReplacer(facgens);
   Add(fgens,Next(pr));
   Add(fgens,Next(pr));
+  Add(fgens,Next(pr));
   if eq(fgens[1]*fgens[2],fgens[2]*fgens[1]) and
      eq(fgens[1]*fgens[3],fgens[3]*fgens[1]) then
       if eq(fgens[2]*fgens[3],fgens[3]*fgens[2]) then
           i := 0;
           while i <= 4 do
               Add(fgens,Next(pr),1);

Alas, I don't have time to properly vet this, or even add a test case, so I am just reporting it here for now

[fingolfin]

Also, this code is crap because it creates a completely new product replacer from scratch (which involves a lot of overhead) instead of reusing one from "somewhere" sigh