config whitelisting: fix some more specs

* missed fixing three calls to xcconfig_relative_path
* Added parens to a call while at it

lib/cocoapods/installer/user_project_integrator/target_integrator.rb

@@ -110,7 +110,7 @@ module Pod
         def add_xcconfig_base_configuration
           native_targets.each do |native_target|
             native_target.build_configurations.each do |config|
-              relpath = target.xcconfig_relative_path config.name
+              relpath = target.xcconfig_relative_path(config.name)
               xcconfig = user_project.files.select { |f| f.path == relpath }.first || user_project.new_file(relpath)
 
               check_overridden_build_settings(target.xcconfigs[config.name], native_target)
@@ -215,7 +215,7 @@ module Pod
                 "Remove the build settings from the target."
               ]
               UI.warn("The target `#{name}` overrides the `#{key}` build " \
-                      "setting defined in `#{target.xcconfig_relative_path}'.",
+                      "setting defined in `#{target.xcconfig_relative_path(config.name)}'.",
                       actions)
             end
           end

spec/unit/library_spec.rb

@@ -36,7 +36,7 @@ module Pod
       end
 
       it "returns the absolute path of the xcconfig file" do
-        @lib.xcconfig_path.to_s.should.include?('Pods/Pods.xcconfig')
+        @lib.xcconfig_path("Release").to_s.should.include?('Pods/Pods.Release.xcconfig')
       end
 
       it "returns the absolute path of the resources script" do
@@ -66,7 +66,7 @@ module Pod
       end
 
       it "returns the path of the xcconfig file relative to the user project" do
-        @lib.xcconfig_relative_path.should == 'Pods/Pods.xcconfig'
+        @lib.xcconfig_relative_path("Release").should == 'Pods/Pods.Release.xcconfig'
       end
 
     end