Support relative redirects when validating URLs.

This fixes CocoaPods/Core#104

lib/cocoapods/validator.rb

@@ -241,7 +241,14 @@ module Pod
           end
 
           if [301, 302, 303, 307, 308].include? resp.status_code
-            url = resp.headers['location'].first
+            location = resp.headers['location'].first
+
+            if location =~ /:\/\//
+              url = location
+            else
+              url = url + location
+            end
+
             redirects += 1
           else
             break

spec/unit/validator_spec.rb

@@ -145,6 +145,18 @@ module Pod
           @sut.validate
           @sut.results.map(&:to_s).first.should.match /The URL \(.*\) is not reachable/
         end
+
+        it "supports relative redirects" do
+          WebMock::API.stub_request(:head, /redirect$/).to_return(
+            :status => 302,
+            :headers => { 'Location' => '/' })
+          WebMock::API.stub_request(:head, /redirect\/$/).to_return(
+            :status => 200 )
+          Specification.any_instance.stubs(:homepage).returns(
+            'http://banana-corp.local/redirect')
+          @sut.validate
+          @sut.results.length.should.equal 0
+        end
       end
 
       describe "Screenshot validation" do