Switch to toybox egrep(1) and grep(1).

Test: treehugger
Change-Id: I9053f45d591a8cb53eb36e258ecb97b591d806a1
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index a4be2ac..175aa28 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -82,13 +82,11 @@
 	"dd":       Allowed,
 	"diff":     Allowed,
 	"dlv":      Allowed,
-	"egrep":    Allowed,
 	"expr":     Allowed,
 	"find":     Allowed,
 	"fuser":    Allowed,
 	"getopt":   Allowed,
 	"git":      Allowed,
-	"grep":     Allowed,
 	"gzcat":    Allowed,
 	"gzip":     Allowed,
 	"hexdump":  Allowed,
@@ -136,9 +134,11 @@
 	"dirname":   LinuxOnlyPrebuilt,
 	"du":        LinuxOnlyPrebuilt,
 	"echo":      LinuxOnlyPrebuilt,
+	"egrep":     LinuxOnlyPrebuilt,
 	"env":       LinuxOnlyPrebuilt,
-	"head":      LinuxOnlyPrebuilt,
 	"getconf":   LinuxOnlyPrebuilt,
+	"grep":      LinuxOnlyPrebuilt,
+	"head":      LinuxOnlyPrebuilt,
 	"hostname":  LinuxOnlyPrebuilt,
 	"id":        LinuxOnlyPrebuilt,
 	"ln":        LinuxOnlyPrebuilt,