Fix broken unit tests of ap_configurator.py.

 - fixed test_band, test_ssid, test_modes and
   test_switching_bands_and_change_settings

BUG=chromium:246377
TEST=Manual (run all 4 test cases and verified passing)

Change-Id: I42f99002a1cf55755a9946ea87408784427e2151
Reviewed-on: https://gerrit.chromium.org/gerrit/58906
Reviewed-by: Kris Rambish <krisr@chromium.org>
Commit-Queue: Tan Gao <tgao@chromium.org>
Tested-by: Tan Gao <tgao@chromium.org>
2 files changed