Also update BUILD.txt

When CK_FORK is set to 'no' the fixtures are executed for every new test
inside of the same process. Global variables must be set to the expected
values by the fixtures.

check_and_open-tests.c: the filename template for mkstemp() was a
globally defined character string. After the first call to mkstemp() the
trailing XXXXXX are substituted by random values, a second call to
mkstemp() with this character string fails. This patch initialize the
filename template before mkstemp() is called with the help of strdup()
and the memory is freed in the teardown fixture.

krb5_utils-tests.c: this patch sets the just freed global talloc context
to NULL to make a consistency check in the setup fixture pass.

If you want to turn verbosity back on, just set the environment
variable CK_VERBOSITY=verbose

* The resolv test case can now test for TXT and SRV resolving by
  specifying -t host and -s host respectively. The -n flag must still be
  passed in to enable network tests.
* Added test for the little complicated resolv_copy_hostent() function.
* Leak checking using the new tests common functions.
* Fix indentation for test_internet, since the whole function was
  modified to be able to handle SRV and TXT replies.
* Initialize the debug variable in main().

Also removed one unused variable in krb5_utils-tests.c

The configuration options krb5ccache_dir and krb5ccname_template
are added to the Kerberos provider to create the user's credential
caches the same way as pam_krb5 does. Due to the design of the sssd
and the supported ccache types of MIT Kerberos only files are
allowed.