Updated tools version to 2.0.0

Also merged lint-style (gofmt) into golangci-lint (enabled gofmt).
Also removed redundant lint-sanity (govet) which is already checked by golangci-lint.
Also made minor code changes to pass new golangci-lint tests.
Also changed lint-mod slightly so it reverts any changes it makes go.mod, go.sum, and vendor/.

VOL-2647

Change-Id: I15557edf0f9225ea1c44e5bab29481d17a82e2b8
diff --git a/rw_core/core/device_ownership.go b/rw_core/core/device_ownership.go
index b616a90..171b91f 100644
--- a/rw_core/core/device_ownership.go
+++ b/rw_core/core/device_ownership.go
@@ -290,9 +290,7 @@
 func (da *DeviceOwnership) deleteDeviceKey(id string) {
 	da.deviceToKeyMapLock.Lock()
 	defer da.deviceToKeyMapLock.Unlock()
-	if _, exist := da.deviceToKeyMap[id]; exist {
-		delete(da.deviceToKeyMap, id)
-	}
+	delete(da.deviceToKeyMap, id)
 }
 
 // getOwnershipKey returns the ownership key that the id param uses.   Ownership key is the parent