Recent GnuTLS disregards the Common Name and only looks at the Subject
Alternative Name extension. Since our test-cert has no SAN extension,
validation fails.
Generate a new certificate with SAN. In addition to 127.0.0.1, for good
measure make it valid for localhost and ::1, too.
https://bugzilla.gnome.org/show_bug.cgi?id=784005
Our ones were expired. The new ones were copied from libsoup's
tests files.
Also sets the property to use our own cert to validate the
server, otherwise the default system certs would be used
and it would fail.
Move unit test data into the directory where it belongs and make in particular
the flacdec unit test cd into the directory with the test files instead of making
assumptions about the current working directory in that unit test. As a side effect
of movng those files, there's only one EXTRA_DIST in tests/check/Makefile.am now,
which is likely to work better than having two. Hopefully fixes#582753.
