Allow deletion of the jiri project.

This is preventing us from moving off of git-mirror, because that will
require a deletion+creation of the jiri project.

Note that the intention of this check is already broken, because we do
allow the deletion of devtools and x/lib, so it's been possible to break
the jiri tool if you update with a bad manifest.

Change-Id: Ib862d27cf6921b12ab3fb799dba93f479b6ad986
diff --git a/project/project.go b/project/project.go
index 9a59667..1aaeb09 100644
--- a/project/project.go
+++ b/project/project.go
@@ -1492,16 +1492,6 @@
 func (op deleteOperation) Run(jirix *jiri.X, _ *Manifest) error {
 	s := jirix.NewSeq()
 	if op.gc {
-		// Never delete the <JiriProject>.
-		if op.project.Name == JiriProject {
-			lines := []string{
-				fmt.Sprintf("NOTE: project %v was not found in the project manifest", op.project.Name),
-				"however this project is required for correct operation of the jiri",
-				"development tools and will thus not be deleted",
-			}
-			s.Verbose(true).Output(lines)
-			return nil
-		}
 		// Never delete projects with non-master branches, uncommitted
 		// work, or untracked content.
 		git := jirix.Git(tool.RootDirOpt(op.project.Path))