tree e979966b9d34b84b91025c378c01380f7117b0bb
parent 91482648070246dbf77e56e80a78687c121f0ddf
author Kent Hagerman <khagerma@ciena.com> 1574284952 -0500
committer khenaidoo Nursimulu <knursimu@ciena.com> 1574368567 +0000

Adding ro-core exclusive api calls to the rw-core.

VOL-2257

There were 10 calls implemented in the ro-core that weren't in the rw-core:
GetVoltha
ListCoreInstances
GetCoreInstance
ListDeviceFlowGroups
ListDeviceTypes
GetDeviceType
ListDeviceGroups
GetDeviceGroup
GetImages
GetMeterStatsOfLogicalDevice

Of these, 5 were stubs: (which were copied over anyways)
ListCoreInstances
GetCoreInstance
ListDeviceGroups
GetDeviceGroup
GetMeterStatsOfLogicalDevice

Altered ListDeviceTypes() and GetDeviceType() to pull from AdapterManager.deviceTypeToAdapterMap rather than going directly to the DB.
Also changed gRPC api calls that returned nil, error to return &type{}, error; and unified returns of this form.

Change-Id: Ib86163bdf6809e84d44632792766c4633534da1b