Update .gitignore

New symbolic link:
test-driver -> /usr/share/automake-1.13/test-driver

Author:    Aurimas Fišeras <aurimas@members.fsf.org>

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23037 57a11ea4-9604-0410-9ed3-97b8803252fd