[Lib lint] Fixes a crash when podspec cannot be loaded

Fixes #2147

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 To install or update CocoaPods see this [guide](http://docs.cocoapods.org/guides/installing_cocoapods.html).
 
+## Master
+
+##### Bug Fixes
+
+* Fixes an issue where `pod lib lint` would crash if a podspec couldn't be
+  loaded.  
+  [Kyle Fuller](https://github.com/kylef)
+  [#2147](https://github.com/CocoaPods/CocoaPods/issues/2147)
+
+
 ## 0.34.0.rc1
 
 ##### Breaking

lib/cocoapods/command/lib.rb

@@ -150,7 +150,10 @@ module Pod
             if validator.validated?
               UI.puts "#{validator.spec.name} passed validation.".green
             else
-              message = "#{validator.spec.name} did not pass validation."
+              spec_name = podspec
+              spec_name = validator.spec.name if validator.spec
+              message = "#{spec_name} did not pass validation."
+
               if @clean
                 message << "\nYou can use the `--no-clean` option to inspect " \
                   'any issue.'

spec/functional/command/lib_spec.rb

@@ -108,5 +108,14 @@ module Pod
         UI.output.should.include 'Pods project available at'
       end
     end
+
+    it 'fails to lint if the spec is not loaded' do
+      Dir.chdir(temporary_directory) do
+        should.raise Pod::Informative do
+          run_command('lib', 'lint', '404.podspec')
+        end
+        UI.output.should.include 'could not be loaded'
+      end
+    end
   end
 end