tests/common.c is now required by all tests (check-based and not),
so we need to properly ifdef it

As with krb5_ccname_template sequences like %u can be used in the
krb5_ccachedir parameter which are expanded at runtime. If the directory
does not exist, it will be created. Depending on the used sequences it
is created as a public or private directory.

One of our resolv tests tries to resolve a nonexistent hostname. Do not
run this test unless we are explicitly told that a network connection
is available (-n). Also do not automatically resolving localhost.

Logs from confdb with missing '\n' in the DEBUG statements annoyed me so
I decided to fix them. I also made a quick grep through the code and
found other places so I fixed them too.

All 'make check' tests will chdir() into this directory before
running the suite. This provides the option of having temporary
files generated in a tmpfs or ramdisk

Adds a new option that tells resolver which address family to prefer or
use exclusively.

Fixes: #404