Rename gitweb-lib.sh to lib-gitweb.sh for consistency with other test
library files.
When it was introduced in 05526071cb (gitweb: split test suite into
library and tests, 2009-08-27) this naming pattern was more
common.
Since then all but one other such library which didn't start with
"lib-*.sh" such as t6000lib.sh has been been renamed, see
e.g. 9d488eb40e (Move t6000lib.sh to lib-*, 2010-05-07).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
