Fixed whole-number float default values missing a .0 suffix.

A previous commit that added "f" for C++/Java/C# would break
on gcc of constants like 3f, which are now output as 3.0f

Tested: on Linux

Change-Id: If9cabbe3c6d6948a5050b8b123bda9c06e181f52

tests/monster_test.fbs

@@ -60,6 +60,7 @@ table Monster {
   testhashs64_fnv1a:long (id:22, hash:"fnv1a_64");
   testhashu64_fnv1a:ulong (id:23, hash:"fnv1a_64");
   testf:float = 3.14159 (id:25);
+  testf2:float = 3 (id:26);
 }
 
 rpc_service MonsterStorage {