libtest: Enable web server logs

Now that we're daemonizing, it's useful to have the logs.  I
wanted this while debugging cookies.

Closes: #651
Approved by: giuseppe

tests/libtest.sh

@@ -262,7 +262,7 @@ setup_fake_remote_repo1() {
     mkdir ${test_tmpdir}/httpd
     cd httpd
     ln -s ${test_tmpdir}/ostree-srv ostree
-    ${OSTREE_HTTPD} --autoexit --daemonize -p ${test_tmpdir}/httpd-port $args
+    ${OSTREE_HTTPD} --autoexit --log-file $(pwd)/httpd.log --daemonize -p ${test_tmpdir}/httpd-port $args
     port=$(cat ${test_tmpdir}/httpd-port)
     echo "http://127.0.0.1:${port}" > ${test_tmpdir}/httpd-address
     cd ${oldpwd}