mac80211: destroy assoc_data correctly if assoc fails

If association failed due to internal error (e.g. no
supported rates IE), we call ieee80211_destroy_assoc_data()
with assoc=true, while we actually reject the association.

This results in the BSSID not being zeroed out.

After passing assoc=false, we no longer have to call
sta_info_destroy_addr() explicitly. While on it, move
the "associated" message after the assoc_success check.

Cc: stable@vger.kernel.org [3.4+]
Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>