Fix 2004/gavin/Makefile and bugs.md (stray item)

When renaming the gavin_install.txt to gavin.md I forgot to update the
Makefile.

In bugs.md there was a stray item for 2004/gavin in the wrong year (yank
paste error almost certainly).

bugs.md

@@ -1408,10 +1408,6 @@ used incorrectly so one should be careful with adding the proper prototypes.
 With this entry it didn't _appear_ to be relevant but maybe it is after another
 change?
 
-
-## [2004/gavin](2004/gavin/gavin.c) ([README.md](2004/gavin//README.md))
-## STATUS: compiled executable crashes - please help us fix
-## STATUS: doesn't work with some 
 # 1997
 
 There was no IOCCC in 1997.