[PodTargetInstaller] Add spec for using the pods own deployment target

lib/cocoapods/installer/target_installer/pod_target_installer.rb

@@ -318,7 +318,7 @@ module Pod
       def deployment_target
         default = Podfile::TargetDefinition::PLATFORM_DEFAULTS[target.platform.name]
         target.specs.map do |spec|
-          Pod::Version.new(spec.deployment_target(target.platform) || default)
+          Pod::Version.new(spec.deployment_target(target.platform.name) || default)
         end.max.to_s
       end
 

spec/unit/installer/target_installer/pod_target_installer_spec.rb

@@ -33,6 +33,14 @@ module Pod
         @spec.prefix_header_contents = '#import "BlocksKit.h"'
       end
 
+      it 'uses the maximum of all spec deployment targets' do
+        spec_1 = Pod::Specification.new { |s| s.ios.deployment_target = '10.10' }
+        spec_2 = Pod::Specification.new { |s| s.ios.deployment_target = '10.9' }
+        spec_3 = Pod::Specification.new
+        @pod_target.stubs(:specs).returns([spec_1, spec_2, spec_3])
+        @installer.send(:deployment_target).should == '10.10'
+      end
+
       it 'sets the platform and the deployment target for iOS targets' do
         @installer.install!
         target = @project.targets.first