Land rapid7#3674, @todb-r7's patch for RangeWalker spec

Author: jvazquez-r7

spec/lib/rex/socket/range_walker_spec.rb

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