Sort upgrade menu by pacman.conf order.

When printing the upgrade menu, sort the repos in the order they are
defined in pacman.conf (or more technically, the order they are
registered in alpm). Packages in the same repo are still sorted
alphabetically.

If a repo is not in pacman.conf or the database query fails it will
fallback to alphabetical.

upgrade.go

@@ -27,15 +27,40 @@ func (u upSlice) Len() int      { return len(u) }
 func (u upSlice) Swap(i, j int) { u[i], u[j] = u[j], u[i] }
 
 func (u upSlice) Less(i, j int) bool {
-	if u[i].Repository != u[j].Repository {
-		iRunes := []rune(u[i].Repository)
-		jRunes := []rune(u[j].Repository)
-		return lessRunes(iRunes, jRunes)
-	} else {
+	if u[i].Repository == u[j].Repository {
 		iRunes := []rune(u[i].Name)
 		jRunes := []rune(u[j].Name)
 		return lessRunes(iRunes, jRunes)
 	}
+
+	syncDb, err := alpmHandle.SyncDbs()
+	if err != nil {
+		iRunes := []rune(u[i].Repository)
+		jRunes := []rune(u[j].Repository)
+		return lessRunes(iRunes, jRunes)
+	}
+
+	less := false
+	found := syncDb.ForEach(func(db alpm.Db) error {
+		if db.Name() == u[i].Repository {
+			less = true
+		} else if db.Name() == u[j].Repository {
+			less = false
+		} else {
+			return nil
+		}
+
+		return fmt.Errorf("")
+	})
+
+	if found != nil {
+		return less
+	} else {
+		iRunes := []rune(u[i].Repository)
+		jRunes := []rune(u[j].Repository)
+		return lessRunes(iRunes, jRunes)
+	}
+
 }
 
 func getVersionDiff(oldVersion, newversion string) (left, right string) {