[Linter] Use the deployment target of the specification.

Closes #304.

lib/cocoapods/command/spec.rb

@@ -241,13 +241,14 @@ def install_pod
         end
 
         def podfile_from_spec
-          name         = spec.name
-          podspec      = file.realpath.to_s
-          platform_sym = @platform.to_sym
-          podfile = Pod::Podfile.new do
-            platform(platform_sym)
+          name     = spec.name
+          podspec  = file.realpath.to_s
+          platform = @platform
+          podfile  = Pod::Podfile.new do
+            platform(platform)
             dependency name, :podspec => podspec
           end
+          podfile
         end
 
         def set_up_lint_environment

spec/unit/command/spec_spec.rb

@@ -106,4 +106,15 @@ def stub_podspec(pattern = nil, replacement = nil)
     linter.lint.should == false
     linter.errors.join(' | ').should.include "The resources did not match any file"
   end
+
+ it "Uses the deployment target of the specification" do
+    spec, file = write_podspec(stub_podspec)
+    spec.stubs(:available_platforms).returns([Pod::Platform.new(:ios, "5.0")])
+    linter = Pod::Command::Spec::Linter.new(spec)
+    linter.quick = true
+    linter.lint
+    podfile = linter.podfile_from_spec
+    deployment_target = podfile.target_definitions[:default].platform.deployment_target
+    deployment_target.to_s.should == "5.0"
+ end
 end