Remove command 'optimize'

It was discovered that the current code may delete still-referenced
blobs, so we'll remove the command for now.

This closes #434

src/cmds/restic/cmd_optimize.go

@@ -1,84 +0,0 @@
-package main
-
-import (
-	"errors"
-	"fmt"
-
-	"restic/backend"
-	"restic/checker"
-)
-
-type CmdOptimize struct {
-	global *GlobalOptions
-}
-
-func init() {
-	_, err := parser.AddCommand("optimize",
-		"optimize the repository",
-		"The optimize command reorganizes the repository and removes uneeded data",
-		&CmdOptimize{global: &globalOpts})
-	if err != nil {
-		panic(err)
-	}
-}
-
-func (cmd CmdOptimize) Usage() string {
-	return "[optimize-options]"
-}
-
-func (cmd CmdOptimize) Execute(args []string) error {
-	if len(args) != 0 {
-		return errors.New("optimize has no arguments")
-	}
-
-	repo, err := cmd.global.OpenRepository()
-	if err != nil {
-		return err
-	}
-
-	cmd.global.Verbosef("Create exclusive lock for repository\n")
-	lock, err := lockRepoExclusive(repo)
-	defer unlockRepo(lock)
-	if err != nil {
-		return err
-	}
-
-	chkr := checker.New(repo)
-
-	cmd.global.Verbosef("Load indexes\n")
-	_, errs := chkr.LoadIndex()
-
-	if len(errs) > 0 {
-		for _, err := range errs {
-			cmd.global.Warnf("error: %v\n", err)
-		}
-		return fmt.Errorf("LoadIndex returned errors")
-	}
-
-	done := make(chan struct{})
-	errChan := make(chan error)
-	go chkr.Structure(errChan, done)
-
-	for err := range errChan {
-		if e, ok := err.(checker.TreeError); ok {
-			cmd.global.Warnf("error for tree %v:\n", e.ID.Str())
-			for _, treeErr := range e.Errors {
-				cmd.global.Warnf("  %v\n", treeErr)
-			}
-		} else {
-			cmd.global.Warnf("error: %v\n", err)
-		}
-	}
-
-	unusedBlobs := backend.NewIDSet(chkr.UnusedBlobs()...)
-	cmd.global.Verbosef("%d unused blobs found, repacking...\n", len(unusedBlobs))
-
-	repacker := checker.NewRepacker(repo, unusedBlobs)
-	err = repacker.Repack()
-	if err != nil {
-		return err
-	}
-
-	cmd.global.Verbosef("repacking done\n")
-	return nil
-}