[Spec Helper] Fix fixture_target_definition

Platform argument didn't worked with custom deployment target

spec/spec_helper.rb

@@ -116,7 +116,8 @@ def fixture_file_accessor(spec_or_name, platform = Pod::Platform.ios)
 end
 
 def fixture_target_definition(name = 'Pods', platform = Pod::Platform.ios)
-  Pod::Podfile::TargetDefinition.new(name, Pod::Podfile.new, 'name' => name, 'platform' => platform)
+  platform_hash = { platform.symbolic_name => platform.deployment_target }
+  Pod::Podfile::TargetDefinition.new(name, Pod::Podfile.new, 'name' => name, 'platform' => platform_hash)
 end
 
 def fixture_pod_target(spec_or_name, target_definitions = [])