Read virtual switch current values correctly

As dev switch and recovery switch may be virtual, crossystem has to
distinguish virtual switches from physical ones.

Since to a virtual switch, its current value should always equal to its
boot value, return a boot value when asked for a current value.

Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>

BUG=chrome-os-partner:10007
TEST=crossystem devsw_cur|recoverysw_cur show correct value on Snow

Change-Id: Ia73147ecd5528a3cc5276aff02a632ce4f52ea8b
Reviewed-on: https://gerrit.chromium.org/gerrit/26568
Commit-Ready: Che-Liang Chiou <clchiou@chromium.org>
Tested-by: Che-Liang Chiou <clchiou@chromium.org>
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
1 file changed