Switch to toybox pgrep(1), pkill(1), and ps(1).

Test: treehugger
Change-Id: Ic357b317e0233a626c89c38df152c3361ee8ea82
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index 5344e3f..305a8f4 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -97,9 +97,6 @@
 	"m4":        Allowed,
 	"openssl":   Allowed,
 	"patch":     Allowed,
-	"pgrep":     Allowed,
-	"pkill":     Allowed,
-	"ps":        Allowed,
 	"pstree":    Allowed,
 	"python":    Allowed,
 	"python2.7": Allowed,
@@ -155,6 +152,9 @@
 	"mv":        Toybox,
 	"od":        Toybox,
 	"paste":     Toybox,
+	"pgrep":     Toybox,
+	"pkill":     Toybox,
+	"ps":        Toybox,
 	"pwd":       Toybox,
 	"readlink":  Toybox,
 	"rm":        Toybox,