Fix rspec due to an invalid dns becoming valid

Author: wchen-r7

spec/lib/rex/socket/range_walker_spec.rb

@@ -25,12 +25,12 @@
     end
 
     context "with an invalid hostname" do
-      let(:args) { "asdf.foo." }
+      let(:args) { "rapid7rapid7rapid7rapid7rapid7rapid7.foo." }
       it { should_not be_valid }
     end
 
     context "with an invalid hostname and CIDR" do
-      let(:args) { "asdf.foo./24" }
+      let(:args) { "rapid7rapid7rapid7rapid7rapid7rapid7.foo./24" }
       it { should_not be_valid }
     end