Add regression-test for description-less repos

Add regression-test for description-less repos

The segfault fixed in commit eacde43d7184452e1fdc90b982b531f1f5239923 was
triggered when the html-functions manipulated string literals. One callpatch
which could trigger the bug is in ui-repolist.c when repo descriptions are
passed to html_ntxt(): if a repo is lacking a description, the literal
string "[no description]" is used.

This patch changes test/setup.sh such that the first repo has no description,
and adds tests for both "[no description]" and "the bar repo" (description
of the other repo) to tests/t0101-index.sh, which should be enought to catch
regressions in these functions.

Noticed-by: Hiroki Hattori <seagull.kamome@gmail.com>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>