[commit/head+branch] Add ChangeLog entry for gdb-6.7 release

[Joel Brobecker]

Hello,

Just for the record, I added an entry in the ChangeLog of both HEAD
and the gdb-6.7 branch to mention the gdb-6.7 release:

2007-10-10  Joel Brobecker  <brobecker@adacore.com>

        GDB 6.7 released.

-- 
Joel