build: remove unused code spotted by the deadcode linter

backend/mega/mega.go

@@ -19,7 +19,6 @@ import (
 	"fmt"
 	"io"
 	"path"
-	"regexp"
 	"strings"
 	"sync"
 	"time"
@@ -114,9 +113,6 @@ func (f *Fs) Features() *fs.Features {
 	return f.features
 }
 
-// Pattern to match a mega path
-var matcher = regexp.MustCompile(`^([^/]*)(.*)$`)
-
 // parsePath parses an mega 'url'
 func parsePath(path string) (root string) {
 	root = strings.Trim(path, "/")