[edit] Always update lockfile if it exists

After this patch, jiri will always update the lockfile if it exist
in current project, even if enforcement of lockfile is not currently
enabled.

Test: CQ
Change-Id: Icb8c3530528f31be42f87447e4c255fc31b51834
diff --git a/cmd/jiri/edit.go b/cmd/jiri/edit.go
index f62855c..bdd19cb 100644
--- a/cmd/jiri/edit.go
+++ b/cmd/jiri/edit.go
@@ -184,7 +184,7 @@
 		return true
 	}
 
-	if len(projects) != 0 && jirix.LockfileEnabled && (editFlags.editMode == lockfile || editFlags.editMode == both) {
+	if len(projects) != 0 && (editFlags.editMode == lockfile || editFlags.editMode == both) {
 		// Search lockfiles and update
 		dir := manifestPath
 		for ; isLockfileDir(jirix, dir); dir = path.Dir(dir) {