README.md: fix name of the ubuntu package containing wpa_supplicant
README.md: fix name of the ubuntu package containing wpa_supplicant

Fixes #51.

autrimpo/rlite,vmaffione/rlite,vmaffione/rlite,autrimpo/rlite,vmaffione/rlite,autrimpo/rlite,vmaffione/rlite,autrimpo/rlite