Fix SPDX license warning
Fix SPDX license warning

Fixes this warning:
npm WARN opendaylight-spectrometer-web@0.0.1 license should be a valid
SPDX license expression

Change-Id: Id11947bbbdec9876a7f319741f1ea5782cb6acbc
Signed-off-by: Thanh Ha <09ea4d3a79c8bee41a16519f6a431f6bc0fd8d6f@linuxfoundation.org>

opendaylight/spectrometer,opendaylight/spectrometer,opendaylight/spectrometer,opendaylight/spectrometer