refactoring: moved compare dashboard version command out of sqlstore, the code in this command did not use any sql operations and was more high level, could be moved out and use existing queries to get the versions

pkg/models/dashboard_version.go

@@ -7,14 +7,6 @@ import (
 	"github.com/grafana/grafana/pkg/components/simplejson"
 )
 
-type DiffType int
-
-const (
-	DiffJSON DiffType = iota
-	DiffBasic
-	DiffDelta
-)
-
 var (
 	ErrDashboardVersionNotFound = errors.New("Dashboard version not found")
 	ErrNoVersionsForDashboardId = errors.New("No dashboard versions found for the given DashboardId")
@@ -77,18 +69,3 @@ type GetDashboardVersionsQuery struct {
 
 	Result []*DashboardVersionDTO
 }
-
-//
-// Commands
-//
-
-// CompareDashboardVersionsCommand is used to compare two versions.
-type CompareDashboardVersionsCommand struct {
-	OrgId       int64
-	DashboardId int64
-	BaseVersion int
-	NewVersion  int
-	DiffType    DiffType
-
-	Delta []byte `json:"delta"`
-}