Lua /etc/resolv.conf parser and some refactoring

test/e2e/lua/dynamic_configuration.go

@@ -20,7 +20,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net/http"
-	"regexp"
 	"strings"
 	"time"
 
@@ -63,13 +62,6 @@ var _ = framework.IngressNginxDescribe("Dynamic Configuration", func() {
 		})
 	})
 
-	It("sets nameservers for Lua", func() {
-		f.WaitForNginxConfiguration(func(cfg string) bool {
-			r := regexp.MustCompile(`configuration.nameservers = { [".,0-9a-zA-Z]+ }`)
-			return r.MatchString(cfg)
-		})
-	})
-
 	Context("Lua shared dict", func() {
 		It("update config", func() {