.gitignore: Ignore a few more auto* files

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
Makefile.am: Compile tests with -no-install

Because a libtool wrapper shell script is useless and a waste of
resources, which also makes debugging harder than it needs to be.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>