tree b831bfeaf42e486f96a3bb23bd5e7eecc3d9d0cb
parent b0328e44788343f84517263e9b4d150d3c20e939
author Yuta HIGUCHI <y-higuchi@ak.jp.nec.com> 1522790826 -0700
committer Yuta HIGUCHI <y-higuchi@opennetworking.org> 1522953859 +0000

make isGroupCapable exception safer

- Tricky part of DriverService API:
  DriverService#getDriver(DeviceId) can either return null or throw exception when not found
  DriverService#getDriver(String mfr, String hw, String sw) will return null when not found

- might fix ONOS-7558

Change-Id: I0a49ab1d94f12e7fda00aa5e8e4bc42820f67dfe