Switch to toybox rm(1).

Test: treehugger
Change-Id: Ib31182ca7ce827396476699ac9d1c636cdd324fc
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index f4ef034..e8e92e6 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -108,7 +108,6 @@
 	"python2.7": Allowed,
 	"python3":   Allowed,
 	"realpath":  Allowed,
-	"rm":        Allowed,
 	"rsync":     Allowed,
 	"sed":       Allowed,
 	"sh":        Allowed,
@@ -162,6 +161,7 @@
 	"paste":    Toybox,
 	"pwd":      Toybox,
 	"readlink": Toybox,
+	"rm":       Toybox,
 	"rmdir":    Toybox,
 	"setsid":   Toybox,
 	"sleep":    Toybox,